Help Me Pick Some Heads For Christmas Present

[Nuckingfuts]

So with Christmas just around the corner I wanted to use the opportunity to pick up some heads for my son's '73 project truck as a surprise. He's been working hard to pay for parts on his own to this point so a little bit of help from Dad isn't a bad thing this time.

The engine is the original rebuilt sbc 350 with the following mods:

- Comp Cams Xtreme Energy Cam & Lifter Kit (11/2010): Summit# CCA-K12-238-2; Cam/Lifter, Valvetrain(timing chain, sprockets, springs, valve stem seals, etc.), Hydraulic Flat Tappet, Advertised Duration 262int/270exh (Actual duration at 050” lift: 218/224), Lift .462int/.469exh. (Stock 350 SBC Cam Spec-estimated: dur @ .050 on that cam is 195/202)

- 1406 EB carb & Performer EPS manifold

- Full length headers, 2.25" exhaust with flowmaster mufflers

- 3.08 gearing

Basically I'm looking to increase low end torque and bump the hp a bit so I'd like to replace the stock heads with something but I just don't know what all of my options are so I'd like to get some direction from you guys. With a budget approach in mind (~$1000), should I get...

1. Rebuild 062 Vortec heads on ebay (~$175/head but I have to send back cores which I don't have so I'm not sure what the extra cost will be here)
2. Summit Vortec heads like this: https://www.summitracing.com/parts/sum-151124
3. Corvette Heads (which are best?)....err, just thinking out loud at this point
4. Another option that you would suggest?


I'd really like to utilize the components we currently have, options that don't require new intake, self aligning rockers, center bolt covers, etc (that the Vortecs require) so I'm definitely interested in hearing more on this point as it might help me keep the cost down and within budget. Hoping you guys can help me come up with a solution that I can put under the tree this year. Thanks for your help!

[techinspector1]

- Comp Cams Xtreme Energy Cam & Lifter Kit (11/2010): Summit# CCA-K12-238-2; Cam/Lifter, Valvetrain(timing chain, sprockets, springs, valve stem seals, etc.), Hydraulic Flat Tappet, Advertised Duration 262int/270exh (Actual duration at 050” lift: 218/224), Lift .462int/.469exh. (Stock 350 SBC Cam Spec-estimated: dur @ .050 on that cam is 195/202)

Nuck, I don't want to upset you or make you mad, but that's way too much cam for an otherwise stock motor. The 1973 Chevy 350's were rated at, I believe, 8.5:1 static compression ratio. Please read this tutorial that I wrote several years ago and you'll see that the stock cam (195 intake) was just right for the motor. When you moved up to the (218 intake) cam, you needed to raise the static compression ratio up to about 9.85:1 to work with the cam. Problem there is, iron heads don't do well with static compression ratios over about 9.5:1 and are subject to causing detonation on pump gas. As a side note, I never liked the Extreme Energy line of cams. They're hard on the valvetrain due to a very low Hydraulic Intensity number and might be ok for a race motor where you want to extract every last hp to drive around a competitor, but for a street motor, they are just too harsh in my opinion.
http://www.crankshaftcoalition.com/w..._compatibility
Wrong cam, along with 3.08 rear gears and likely stock torque converter are why the truck is a pooch.
Other thing is, flat tappet cams are a relic from the past century. You have to jump through all kinds of hoops to get them to live and they give up hp as compared to a hydraulic roller tappet cam. Read on......
http://www.crankshaftcoalition.com/w...ips_and_tricks

- 1406 EB carb & Performer EPS manifold

Nothing wrong with a 600 CFM carb to take Grandma to Bingo, but you will need more CFM eventually. A Chevy 350 makes maximum power with a 750 carb, not that you'll need that much carburetor until you fix some of the other stuff. Wrong intake manifold. Motor needs a high-rise, dual-plane intake such as an Edelbrock Performer RPM or Weiand 8150. There are two such dual-plane, high-rise manifolds that are out of production but can be found used on craigslist or ebay or at local swap meets sometimes, Holley 300-36 and Weiand 8014. If I had to buy one today, it would be the Holley 300-36.

- Full length headers, 2.25" exhaust with flowmaster mufflers

Cobble up an "X" pipe and install it immediately after the collectors. If you chose headers with flange material of less thickness than 3/8", be prepared for them to warp up like a potato chip and spit out the gaskets.

- 3.08 gearing

Here's the other major problem. The cam is not a stand-alone part in the motor. It must be coordinated with other parts in the motor to reach a certain goal. You should have changed gears, along with raising the static compression ratio, when you changed the cam. New spring rubber, new shocks, a 3.73 limited slip ring and pinion and some wider wheels and tires would have been the ticket. (This might be a nice Christmas present). The other problem will be the stock torque converter. An aftermarket converter that is matched to the cam will do wonders for acceleration.

Basically I'm looking to increase low end torque and bump the hp a bit so I'd like to replace the stock heads with something but I just don't know what all of my options are so I'd like to get some direction from you guys. With a budget approach in mind (~$1000), should I get...

L31 heads are the best flowing PRODUCTION cast iron heads that Chevy ever produced, but they need some help to be used on motors other than the L31. Here's a decent write-up......
http://www.crankshaftcoalition.com/w..._cylinder_head

1. Rebuild 062 Vortec heads on ebay (~$175/head but I have to send back cores which I don't have so I'm not sure what the extra cost will be here)
2. Summit Vortec heads like this: https://www.summitracing.com/parts/sum-151124
3. Corvette Heads (which are best?)....err, just thinking out loud at this point
4. Another option that you would suggest?

I would suggest a nice set of aluminum heads, like Profiler 185's, but then you'd have to completely disassemble the motor to cut the block decks in order to use the thicker composition head gaskets that the manufacturers recommend. Using steel shim head gaskets with aluminum heads will "fret" the aluminum and wear it away. This is because of the differential of heating and cooling between the cast iron block and the aluminum heads. A zero-deck motor using a ~0.040" thickness head gasket will produce a squish/quench of 0.040", making the motor as detonation-resistant on pump gas as it will ever be. Using a composition gasket with a stock piston deck (about 0.025") will result in a squish/quench of about 0.065", much too wide to be effective in preventing detonation.

I'd really like to utilize the components we currently have, options that don't require new intake, self aligning rockers, center bolt covers, etc (that the Vortecs require) so I'm definitely interested in hearing more on this point as it might help me keep the cost down and within budget. Hoping you guys can help me come up with a solution that I can put under the tree this year. Thanks for your help!

Problem is, you don't have any performance parts to begin with. Remove the cam and replace it with a hydraulic roller with intake not to exceed 204 degrees. Crane 119811 is just one example, having a lobe separation angle of 112 degrees to facilitate power brake vacuum. Install a set of 3.73 rear gears with limited slip and if you have money left over, purchase a 10", 2500 stall converter. Wider rear wheels and tires will help to transfer your newfound power to the pavement and you'll think you have swapped a big block into the truck.

Don't be fooled into buying a cheapo 12" converter with the fins bent over, buy the genuine 10" unit.
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[Mike P]

Just some thoughts from an old man.

I’m going to assume that the truck is intended to be a daily driver?

It’s also going to be used and learned on by a new 16 year old driver.

As parents/grandparents/mentors and instructors it’s pretty easy to lose sight of the skill level and abilities of the new driver and end up building more vehicle than they can safely handle. It’s real easy to end up building something that is more suited to our skill level than theirs.

That being said I think my approach would be to turn this into a truly long term project where more power is gradually added over time as your sons driving skills develop. It also ends up giving you more quality time with your son down the line as the mods are made.

As usual Richards suggestions are all good but it’s something that can be done over time as skills and funds permit. Personally at this point I would concentrate mainly on just plain reliability.

In that vein (and budget) rather than heads right now I think I would probably look more to the hydraulic roller cam Tech suggests. Basically build a good foundation for the future mods. The next area I would consider upgrading would be the gears in the rear end and that will depend in large part on the tire size your running.

Anyway, that’s just my 2 cents.



.

[Nuckingfuts]

Richard that's quite the laundry....er Christmas list.
Seriously though, thank you for the thoughtful reply and the reason I signed up here. I've never been afraid to turn a wrench but my knowledge on motor building is squat and I'm serious about learning, and learning the right approach at that.

We picked up this truck about 6 months ago and have slowly been working through the truck to address parts that need replacing/restoring (other than engine/trans). The previous owner had done the cam swap, intake, etc. so I didn't have a say in that one but the parts installed are relatively new which is why I was hoping to utilize them if at all possible.

I did have gearing change on our short list though and I was thinking along the lines of 3.43 since the TH350 is currently outback and with plans to swap in a 700R4 for the OD. When we cross that bridge, and if budget allows, I'll consider a GM4L80E but right now this is considered a budget minded build to learn from. Regarding the torque converter, yes it's stock and don't yet understand the selection process to chose the correct one. If you know of a good learning resource I'm all ears.

As Mike pointed out (great wisdom added to the conversation btw), this is indeed going to be his daily driver and something that will be a work in progress over the long-term. With that said I'm willing to put the heads on the back burner for now in favor of a sound long term strategy which re-prioritizes my power train build as such:

1. Re-gear rear end
2. New hydraulic roller cam
3. New torque converter

I'll be reading up on the links you provided so I'll hold off on my questions until then. If you have suggestions on specific cam packages that I should be focused on please let me know, this will give me an opportunity to stick something under the tree.

Mike I'll try and get some photos of the truck up on my "Hello from SJ" thread later today.

[glennsexton]

Great post – Welcome to CHR!

As you’ve already ascertained, Tech is a fountain of knowledge – listen and soak up his wisdom. I’ve been roddin’ almost as long and he continues to teach me!

If you have not bought the 700R4, I’d suggest a 200R4. For the most part it is a bolt-in replacement of your TH350.
1. You re-use your current the driveshaft with no modifications whatsoever required. A 700R4 requires driveshaft to be shortened.
2. You can use your existing cross member – needs to be moved back 6 inches and new holes drilled - use Grade 5 or better bolts.
3. Same transmission cooler lines as the TH350.
4. Same shift linkage (can even get a new little window showing all 4 gears).
5. Same throttle cable and cable bracket at the carb.

There’s also the ratios – your TH350 is 2.52 in first. The 200R4 is 2.74 and the 700R4 drops to 3.06. Might not sound like a big deal but is huge on takeoff. Also at the other end, the OD on the 200R4 is .67 where the 700R4 is .70 – not huge but at speeds below 50-60MPH (depending on rearend ratio and tire size) there will be a lot of 3rd to 4th to 3rd going on.

I’d also second the Chevrolet Performance 12558060 (L31) heads. They’re readily available from several sources and a pair will be well below a grand – even with gaskets and some polished aluminum valve covers. Bear in mind that a new intake is required but Summit, JEGS and others have a kit that includes everything you need for this swap.

Ditto on the cam selection as well. I’ve installed a ton of flat tappet cams with very little trouble but the writing has been on the wall for some time as to their future – rollers are certainly the way to go.

Most important in this whole post is the father son aspect of the project. I bought my son a ’71 C10 when he graduated from high school. 350/350 real stock. We swapped the original intake for a dual plane aluminum, Edelbrock 1406 (yes – it was tamer that the stock Quadrajet), big free breathing air cleaner, Hooker ceramic headers, and HEI ignition. Went with 285/60 15 tires and GM SS rims, new Cheyenne interior and a tilt column. That was 13 years ago and it’s running like a champ – very fun to drive and he still loves it. I can not tell you how fantastic it is to see him and his beautiful wife snuggled together on that big bench seat to go for a drive. I have a new performance Q-Jet to re-install at some date, but the truck is just a great ride as is.

Have fun with this – memories will be made.

Glenn

[techinspector1]

Nuck, here's a pretty good read on the operation of looser than stock torque converters....
What does a high stall torque converter do?

Stock converters were designed by the factory to keep engine speeds and subsequent noise down on launch and to transport Granny to Bingo once a week or take the family to the grocery store. They were not designed for increased acceleration.

Here's a decent tutorial by Eric the Car Guy. He gets it a little wrong at the end, where he's looking at the camera and talking, but for understanding the internals of a torque converter, he does a pretty good job.....
https://www.youtube.com/watch?v=pTfipsejqS0
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[Nuckingfuts]

I've gotten through some of the reading regarding cam choices and their relation with regard to CR but I'm still getting hung up on the proverbial "did the chicken or egg come first?". In my case, do I install the heads or cam first?

What's the proper approach here if I want to target a SCR of 9.5:1 (assuming iron heads), do I

a) Choose a cam that best works for 9.5:1 then install heads/shim gaskets (and possibly pistons) to achieve the target SCR?
b) Choose a head to achieve my target SCR first, then install a cam that works best for the new SCR
c) Match, spec and install the cam and heads at the same time

Ideally I would think option 'c' would be the correct answer but because of budget constraints this option is out. If I go with option 'a' do I just use my target set up to make the choice? This puts me back to square one, choosing a set of heads to increase my SCR which after established would help me to choose the proper cam per everyone's advice. Thoughts?

[Nuckingfuts]

Glen that's a GREAT option that I wasn't aware of. Definitely going to go this route! Thank you sir.

[Nuckingfuts]

Nuck, here's a pretty good read on the operation of looser than stock torque converters....
What does a high stall torque converter do?

Here's a decent tutorial by Eric the Car Guy. He gets it a little wrong at the end, where he's looking at the camera and talking, but for understanding the internals of a torque converter, he does a pretty good job.....
https://www.youtube.com/watch?v=pTfipsejqS0
.

Richard, thank again for the links. I'm almost caught up on the previous links and will get into this info right after.

[techinspector1]

I've gotten through some of the reading regarding cam choices and their relation with regard to CR but I'm still getting hung up on the proverbial "did the chicken or egg come first?". In my case, do I install the heads or cam first?

What's the proper approach here if I want to target a SCR of 9.5:1 (assuming iron heads), do I

a) Choose a cam that best works for 9.5:1 then install heads/shim gaskets (and possibly pistons) to achieve the target SCR?
b) Choose a head to achieve my target SCR first, then install a cam that works best for the new SCR
c) Match, spec and install the cam and heads at the same time

Ideally I would think option 'c' would be the correct answer but because of constraints, this option is out. If I go with option 'a' do I just use my target set up to make the choice? This puts me back to square one, choosing a set of heads to increase my SCR which after established would help me to choose the proper cam per everyone's advice. Thoughts?

Remember I said earlier that the last two things you buy for a project are the cam and the torque converter?

I was under the impression that you were not going to change pistons. Are you going to leave the stock pistons in the block or change them out? Because that could change the whole complexion of this project. You might begin thinking 383.

It's just a matter of alloting a certain amount of money per month to the project. Few of us have had a lump of cash to build what we wanted to right out of the box. I used to work on a $50/week budget in the early days. Sometimes a project would take 5 or 6 years to fruition, but it was something that I loved doing, so I kept at it. Mama was good with it because it kept me close to home. I remember waiting 10 weeks to buy a set of coilover shocks on a roadster project.

The closer I got to finished on a project, the more interest there was among my friends and their friends and sometimes, someone would offer me more money for the project than I thought it was worth at that point and it would go down the road and that would give me a jump-start on the next project. That's what happened to my 392 hemi in an MGA roadster on a chopped Galaxie chassis and my '27T roadster on a homebuilt 2" X 6" chassis with a 429/C6/9" projects, as well as several others. Some other projects, like the VW bug on a '62 Olds Starfire chassis with a 394 were stillborn and sold off for parts. Not everything turns out like you envision it. For me, it was always about the building it, rather than the driving of it.

I keep thinkin' that there is one more project in me and that's what keeps me going at my age. I would love to do a blown 302 in a Miata with a paddle-shifted 6-speed. That's one that I would want to drive.......
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[Nuckingfuts]

Remember I said earlier that the last two things you buy for a project are the cam and the torque converter?

I was under the impression that you were not going to change pistons. Are you going to leave the stock pistons in the block or change them out? Because that could change the whole complexion of this project.
.

Ok I got it this time. The details are registering but I just hadn't prioritized them in my head yet. So prioritizing our list,

1. Change rearend gearing
2. Get the compression up by way of an iron head (I had no intentions of swapping pistons unless you suggested otherwise, glad I don't have to)
3. New hydraulic roller cam set with 204 intake duration (your article chart shows a 212 duration cam for a 9.5:1 SCR though??)
4. 10" torque converter

[techinspector1]

[QUOTE=Nuckingfuts;572955]Ok I got it this time. The details are registering but I just hadn't prioritized them in my head yet. So prioritizing our list,

1. Change rearend gearing

Unless someone has changed out the differential sometime during the truck's life, I'm pretty sure it came equipped with a 12-bolt GM. Count the bolts holding the rear cover on.....
https://www.ringpinion.com/b2c/DiffD...&DriveType=RWD
We touched briefly on the ratio that would work best. Having been part of many different discussions and witnessing many different builds concerning the proper ratio, I have concluded that a 3.73 ring & pinion will work best with an overdrive transmission. I say discussions and witnessing builds because I never have and never will use an overdrive transmission on a hot rod build and I'll never advise anyone else to do it either. I feel that the only reason to use an overdrive transmission is for fuel mileage and I am not interested in fuel mileage in my hot rod. Fuel mileage is for my daily driver that comes from the factory with an overdrive transmission that I will never touch.

I see fellows using an overdrive transmission with a hot rod cam. Makes no sense to me. Any hot rod cam that you might choose (like the 204 that I like for your truck, has a minimum cruise rpm of 2200-2600 rpm's. Now, I ask you, how are you going to make any fuel mileage if you have to run the motor at 2200-2600 minimum. If you gear the rig to run down the highway at 1600-1800 rpm's, you are out of the range of minimum cruise rpm's that the cam grinder specified for that cam and you are not generating any fuel mileage anyway. Can you see the lunacy in this? You either drive a hot rod or you drive a stock cam rig. You cannot have it both ways, not with a carbureted rig at least. (224 intake cam-3000 to 3400 cruise rpm), (236 intake cam-3800 to 4200 cruise rpm). I hope you can see this, that the wilder the cam, the stupider the idea of an overdrive transmission becomes. If you want to run an overdrive transmission, put a stock cam in the motor, enjoy the ride and leave that hot rod nonsense to someone else.

So, that leaves me (Henry Hotrod) with either a 2-speed Powerglide or a 3-speed TH350 or TH400, or a C4 or C6 if using Ford motivation. With any of these choices, I will still use a 3.73 gear on a street driver. It's good for cruising and it's good for acceleration. If I were to build for a street-strip vehicle, I would gear it up into the 4's. I guess my all time favorite sound would be the fellow from my neighborhood who drove a '57 Chevy with a Rock Crusher Muncie 4-speed running through 4.56 gears and the sound of a Quadrajet opening up. Sounded like 14,000 rpm's if you know what I mean.

I would begin by contacting the differential specialty companies, such as Currie Enterprises or Moser Engineering and talking with the tech guys about the ring and pinion, a limited slip pig of some kind and axles. Sometimes these guys will know of a complete unit that is for sale somewhere. (I like the Auburn Limited Slip units).
Tech Support | Moser Engineering
https://www.currieenterprises.com/contactus-2
https://www.richmondgear.com/contact...ts-components/

2. Get the compression up by way of an iron head (I had no intentions of swapping pistons unless you suggested otherwise, glad I don't have to)

Pull a valve cover and find the casting number of one of the heads (cast in between the springs or pushrod holes). That's the easiest way to look up your heads and find out the combustion chamber volume. Then I can teach you how to find the static compression ratio through common math. Production heads are generally 64 or 76 cc's, so there may not be a lot of room to arrive at the SCR that you want with a production head.

3. New hydraulic roller cam set with 204 intake duration (your article chart shows a 212 duration cam for a 9.5:1 SCR though??)

A 204 cam will work all the way through 9.5:1. If I were building your motor, I would not use any more cam than that.
The chart is showing "ideal" and there is a little wiggle room either way.

4. 10" torque converter

A 10", 2500 stall unit would be just right right in my opinion. Just like with gears, lean on the manufacturers. Call 'em up an yack with 'em. They won't bite.
Contact Us - Hughes Performance
https://www.coanracing.com/contact-us
ATI Tech Support
I've known Jim Hughes for nearly 30 years, so if you can, try to give him your business. He does a lot to support racing and is a good guy. When I teched at Firebird years ago, Jim would always have a hot meal ready at his pit for any of the race crew, not just once in a while, but at every event. I paid him back by teching his car(s) at his pit, saving him time and effort from loading up and going to tech up on the hill. And by the way, I never, ever found anything wrong with Jim's car(s). First class operation all the way.
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[Nuckingfuts]

Richard I've gotta start by saying, you're good man! You've got 30+ years on me but I can remember even back as a young man gravitating toward the 'old guys' because they were chalked full of knowledge and willing to mentor to any young guys that showed a genuine interest to learn what they had in their noggins. You my friend are one of those inspiring mentors to us younger generations, I appreciate your time sir!

Yes this truck is equipped with a 12 bolt rear end. I've never attempted to change gearing but I'm not afraid to tackle the job if I can't find a 3.73 geared rear end for a reasonable price. The bay area here is a joke with regards to pricing on certain parts, rear ends being one of them. Tare down is straight forward, I just need to get up to speed with the install protocol, setting lash, etc. I'd actually prefer to do it myself as it's one of those things that's still a grey area and as an engineer, I must scratch any itch I don't understand. Either way I'll look into your suggested diff guys to see what the options are before making a decision.

I hear your logic on the OD transmission and will take that into consideration. Transmission change is way down the list so I'm too worried about that anyway. Most of my son's driving will be to/from school, sports and Friday night hops for the next 3 years so a 3.73 3-gear set up would be just fine. My older daughter's Jeep got 12.5 mpg during her high school years and because the drive mileage was so low it didn't hurt my wallet too bad.

I'm almost positive these stock heads are the 76cc's (but I had planned to pull the covers off at some point to confirm) so I'm not sure how much can be gained with these heads. I'm open to suggestions though and can pull a cover this weekend to confirm if it helps.

Ok so the 204 cam, I'm gathering that the 3.73 gearing, 3-speed, and a compression bump to 9.5:1 from heads is all meant to optimize low end, off the line performance and the 204 cam with 112 LSA to compliment and balance out the system for a wider power band and better drivability. Question, since higher valve lifts produce more hp, what's the highest lift I can get or want?

On the TC, I still have to get through your earlier links but I intend to this weekend then I'll follow up on your lead and contact Jim's group to get some input.

Thanks again Richard!

[techinspector1]

Richard I've gotta start by saying, you're good man! You've got 30+ years on me but I can remember even back as a young man gravitating toward the 'old guys' because they were chalked full of knowledge and willing to mentor to any young guys that showed a genuine interest to learn what they had in their noggins. You my friend are one of those inspiring mentors to us younger generations, I appreciate your time sir!

Thanks very much Nuck. I had quite a few fellows help me along the way and I see it as a responsibility to pass on what I have learned because I love it so and would like others to feel the same way about it.

Yes this truck is equipped with a 12 bolt rear end. I've never attempted to change gearing but I'm not afraid to tackle the job if I can't find a 3.73 geared rear end for a reasonable price. The bay area here is a joke with regards to pricing on certain parts, rear ends being one of them. Tare down is straight forward, I just need to get up to speed with the install protocol, setting lash, etc. I'd actually prefer to do it myself as it's one of those things that's still a grey area and as an engineer, I must scratch any itch I don't understand. Either way I'll look into your suggested diff guys to see what the options are before making a decision.

All these years, whenever I took on a new project, I would contact Faxon Auto Literature for a complete set of service manuals on the car or truck that I was intending to modify. Chilton and Motors manuals basically say "disassemble" and re-assemble in reverse. I have found them worthless, so was very happy to find Faxon years ago and be able to purchase the original manuals from the manufacturers.
Search

Looking at the offerings, first up is a 957 page Service Manual. Very good would be almost like new and good would be perfectly acceptable and serviceable. You'll want the 510 page Overhaul Manual, as overhauls are not included in the Service Manual. Or you can get both Service Manual and Overhaul Manual together on a CD if you have access to a printer and would rather not buy the books.

The wiring diagram is offered as a reprint or original.

If it were my truck, I would want an Owner's Manual to put in the glovebox. This is a nice addition when you go to sell the truck. Never say never.

Finishing off the original GM stuff is a CD-ROM parts illustration and a printed parts interchange manual 1973 to 1987. This is where you'll find the stouter sway bars. The remainder of literature shown is all aftermarket and is available from many different outlets.

I hear your logic on the OD transmission and will take that into consideration. Transmission change is way down the list so I'm too worried about that anyway. Most of my son's driving will be to/from school, sports and Friday night hops for the next 3 years so a 3.73 3-gear set up would be just fine. My older daughter's Jeep got 12.5 mpg during her high school years and because the drive mileage was so low it didn't hurt my wallet too bad.

Simpler is better.

I'm almost positive these stock heads are the 76cc's (but I had planned to pull the covers off at some point to confirm) so I'm not sure how much can be gained with these heads. I'm open to suggestions though and can pull a cover this weekend to confirm if it helps.

Yes, with an 8.5:1 SCR, I would bet they're 76 cc's. When we find out what they are for sure, we'll be able to look around for some replacements with smaller chambers.

Ok so the 204 cam, I'm gathering that the 3.73 gearing, 3-speed, and a compression bump to 9.5:1 from heads is all meant to optimize low end, off the line performance and the 204 cam with 112 LSA to compliment and balance out the system for a wider power band and better drivability. Question, since higher valve lifts produce more hp, what's the highest lift I can get or want?

Lift will be dictated by the duration of the lobe and whether or not the cam is ground on a full diameter blank or a reduced diameter blank. (Smaller base circle). Reduced diameter blanks are used to prevent interference with a few cam lobes and the big end of the connecting rod on a stroker motor such as the 383 Chevy. (4.030" X 3.750")

If this were a drag race vehicle and you were 2/10ths of a second off the National Record in your class, I would advise you to go to 1.6:1 ratio rocker arms. For any other situation, I would advise keeping the stock 1.5:1 ratio rockers. The valvetrain is probably the most highly stressed system in the motor and there is no use in asking more of it than it can produce, trouble-free, over a long period of time. I have seen an average of a 10-12 horsepower gain in a 500 hp motor by changing to 1.6 rockers.

On the TC, I still have to get through your earlier links but I intend to this weekend then I'll follow up on your lead and contact Jim's group to get some input. Thanks again Richard!

.

[Nuckingfuts]

Just for completeness I want to summarize the suggested head options for my specific case in order to narrow my focus,

1. Rebuilt '96 and up Vortec heads (unless these came from a reputable source I'm not willing to gamble here)
2. Summit Vortec Heads (slightly above budget but an iron head that has respectable flow and quality - Dart mfg.)
3. EngineQuest EQ-CH350HA https://www.ebay.com/itm/Chevrolet-350-New-Assembled-Cylinder-Head-1969-1985-PAIR-vortec-chamber/142427006944?hash=item21294fa7e0:gMoAAOSw7ThUkH4f&rmvSB=true (Though EQ heads get solid reviews overall, this 'hybrid' head which allows the use of standard intake manifold, has questionable performance as a result)
4. GM 'L31' Style Heads: https://www.summitracing.com/parts/nal-12558060 (do I need to worry about heads like this that have pressed in studs vs thread rocker arm studs?)
5. Brodix 180's (very enticing reviews but these are aluminum with a slippery slop I'd like to stay away from on this build)

So far I guess it comes down to #2 & #4