383 for towing a travel trailer

Anyone built a 383 SBC for towing? Anyone have any recomendations? It is going in a 74 Chevy 1/2 ton pickup with a TH400.
What I am going to do is pull out the 2 barrell 145 HP 350 and Th350 tranny and install a 383 with a TH400 for towing my 25' 4500 lb.travel trailer. I want to build the ultimate tow machine without having to buy a new truck for 25-40K. I already bought a used 90 3/4 ton pickup, and 2 O/D trannies later, I want to start with and older truck without a catalytic converter and build something for around $10,000. I bought a 1974 C10 with 54,000 original miles that is great shape. I am looking for torque more than HP at the 3000 RPM range, and on a VERY lean budget.

What I have so far is:
74 350 4 bolt main bored .030 over
Enginekits.com 383 balanced kit flat top pistons
Weiand 8150 intake
Holley 750 vac secondaries
Comp cams 12-262-4 cam
Heads are 882 casting numbers(Most likely 1.94, I know not the best) 76cc

Yep, got 'er right here.

KB135 hyper D-cup pistons, 18cc dish, hung on 5.7 rods. Pay close attention to KB recommendations for top ring end gap.
L31 Vortec heads, 1.94/1.50 valves. Stock except Comp springs and retainers. See spring requirements on cam card.......
http://www.compcams.com/Cam_Specs/Ca...x?csid=85&sb=0
Talk with Comp about using springs that have these specs, but are the same diameter as the spring seats in the stock heads to prevent having to spend money cutting new spring seats. There are some super-keen Beehives available for this application.
1.750" long-tube, equal-length headers with "X" pipe right after the collectors and 2 1/2" pipe to the rear through mufflers of your choice.
Edelbrock Performer RPM dual-plane, high-rise intake manifold mounting a 600 cfm carb of your choice. Cam advanced 2 degrees. 9.700:1 static compression ratio, 8.384:1 dynamic compression ratio. Set squish between 0.035" and 0.040". Stack will measure 9.008". If you need a little thinner gasket than normal to set your squish, a Victor Reinz #5746 compresses to 0.025". This combination makes a nice torque motor......
RPM HP TQ
1000 62 328
1500 113 397
2000 164 430
2500 206 432
3000 256 448
3500 308 461
4000 348 457
4500 379 443
5000 392 412
5500 365 349

Now, I just happen to like the L31 heads, but you could certainly do it close to these results with the GM 882 heads. You would have to use different pistons though, because the 882 heads are 76cc's. Use KB134 flat-tops to achieve the same 9.700:1 static compression ratio we had with the L31 heads.
RPM HP TQ
1000 62 325
1500 112 393
2000 163 427
2500 205 431
3000 256 448
3500 308 462
4000 348 457
4500 377 440
5000 387 407
5500 344 329

Changed to 750 carb and CompCams 12-262-4 because the OP already has this cam. This cam is for a computer controlled engine, but will work with a carbed unit like we are using here. The timing opening and closing points are a little different, but it's basically the same cam used on the other two sims.
http://www.compcams.com/Cam_Specs/Ca...x?csid=92&sb=0
Cam installed straight up on the marks.
RPM HP TQ
1000 63 330
1500 111 389
2000 160 420
2500 201 422
3000 253 444
3500 309 463
4000 354 465
4500 386 451
5000 400 420
5500 359 343

Dropping down to 1 5/8" on the header tube size drops 5 hp and 3 ft/lbs of torque, so if it's easier to fit the smaller tubes, I'd do it. DO NOT GO ANY SMALLER THAN 1 5/8". Using those cheezy "shortie" headers however, will drop 36 hp and 32 ft/lbs of torque, so I wouldn't do that. Stock cast iron manifolds drop 54 hp and 50 ft/lbs of torque down low where you need it.

The key to making this whole mess work on pump gas with a 9.7:1 static compression ratio and iron heads is the squish. In order to have a good, strong squish of fuel/air mixture jetted across the chamber, you need to have a nice, flat area on the piston crown to mate up with the underside of the cylinder head. This type of piston crown WILL NOT WORK.....
http://store.summitracing.com/largei...=stl-423np.jpg

This type of piston crown WILL WORK....
http://store.summitracing.com/largei...l2256f60_w.jpg

And if you need a dish piston to reach your target static compression ratio, use a D-cup piston such as this. Notice the nice flat crown area on the right side of the photo. This is the part of the piston that will mate up with the underside of the head to create squish.....
http://kb-silvolite.com/performance....etails&P_id=92

I updated my original question with more info. But what about using the 882 cylinder heads that are on the motor? I know that they are the later ones that are prone to cracking, but since I am not looking for HP, but torque, couldn't these heads be massaged to work? If I have to buy a set of wrecking yard L31 heads, and then have them rebuilt, wouldn't it be better to buy some new heads from Summit or jegs?

The kit comes with these pistons: They are cast, but since this engine will never see even 4500 RPM, I am hoping they will work okay.

http://store.summitracing.com/partde...0&autoview=sku

Also, I called the comp cam hotline and they recomended this cam: It is a little more agressive than the one you recomended. What do you think?

http://www.compcams.com/Cam_Specs/Ca...x?csid=92&sb=2

This is the kit for the 383: It comes with speed pro cast flat top pistons.

https://shop.enginekits.com/osb/itemdetails.cfm?ID=81

Also, the comp cam tech line recomended this cam:

http://www.compcams.com/Cam_Specs/Ca...x?csid=92&sb=2

This one is a little more agressive than the one you recomended. Do you think that this cam is to much?

Built basically the same as you've outlined and yes it was a TORQUE MONSTER. pulled a 32 ft trailer all over the western U S., also had a Gear Vendor in it.

Added some stuff to post 2, so will push it back to the top for all to read....

Well, call it my first mistake. I ordered the 1 1/2" Summit "Budget" full length headers for the C 10 pickup...be here tomorrow.

Summit SUM-G9006

Believe it or not I have the "Cheezy" shorty headers on my 63 Nova so I could keep my stock column shift and they actually work pretty good.

"they actually work pretty good."

No they don't, you just don't know the difference.

So everything on the Sanderson website is a lie? Or for a medium motor in a tight engine compartment, they would tons better than using exhaust manifolds.
I have a 350 with flat-top pistons, 76cc, 1.94/150 heads, roller rockers, Edelbrock performer intake with an Edlebrock 750 using a comp cams 12-242-2(XE268H). How much horsepower difference would long tube headers make as opposed to the Sanderson headers below 5500 RPM? My guess would be not enough to have to cut a hole in the floor in all original Nova to accomodate a floor shifter.

http://www.sandersonheaders.com/tech_get_technical.php

How much HP and torque drop will 1 1/2" long tube headers have.....at 3500 RPM?

"Dropping down to 1 5/8" on the header tube size drops 5 hp and 3 ft/lbs of torque, so if it's easier to fit the smaller tubes, I'd do it. DO NOT GO ANY SMALLER THAN 1 5/8".

Quote:

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Originally Posted by jbright300

How much HP and torque drop will 1 1/2" long tube headers have.....at 3500 RPM?

"Dropping down to 1 5/8" on the header tube size drops 5 hp and 3 ft/lbs of torque, so if it's easier to fit the smaller tubes, I'd do it. DO NOT GO ANY SMALLER THAN 1 5/8".

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1 3/4" headers 463 ft/lbs @3500
1 1/2" headers 433 ft/lbs @3500

You choose.

Since I have already purchased the 1 1/2" headers, how can I make up the 30lbs of torque?

Ummmm, have you thought about selling the small headers and buying the correct ones?

Quote:

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Originally Posted by jbright300

Since I have already purchased the 1 1/2" headers, how can I make up the 30lbs of torque?

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Small huffer would be nice.

They headers are already on the truck. Even though I am not ready for the engine overhaul, when I bought the truck last week, the exaust system was in bad shape.(Both exhaust manifolds were cracked and the muffler was blown out). So in order for me to even drive the thing until I am ready to pull the engine, I had to put a complete exhaust system on it.

The truck I have been pulling my trailer with is a Ford f250 extra cab, 3/4 ton with a 351W(210 HP, 315 lbs. of torque). My goal is a Chevy small block with 350+ HP and 400+ lbs of torque at about 3000 RPM.

So if these smaller headers take away 30 lbs of torque. it will just have to do for now.

Quote:

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Originally Posted by jbright300

They headers are already on the truck. Even though I am not ready for the engine overhaul, when I bought the truck last week, the exaust system was in bad shape.(Both exhaust manifolds were cracked and the muffler was blown out). So in order for me to even drive the thing until I am ready to pull the engine, I had to put a complete exhaust system on it.

The truck I have been pulling my trailer with is a Ford f250 extra cab, 3/4 ton with a 351W(210 HP, 315 lbs. of torque). My goal is a Chevy small block with 350+ HP and 400+ lbs of torque at about 3000 RPM.

So if these smaller headers take away 30 lbs of torque. it will just have to do for now.

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Alrighty then.

What about roller rockers? To get more midrange torque, is there any adavantages to using the 1.6 ratio rockers on both intake and exhaust or on just the intakes?

Full rollers will free up a little power due to reduced friction. In my opinion though, I wouldn't use 1.6's with an Extreme Energy cam like I used for the DynoSim pull. These cams are ground at the maximum lifter rise without the lifter digging into the side of the cam lobe and are already at the max for lifter/lobe pressure in my opinion. Putting more pressure on the lifter/lobe interface would be asking for trouble.

Okay, 1.5's it is. That is just one more piece to the puzzle.

There was a good article in Car Craft that built a budget 383 with Vortec heads(The ones you like) and the numbers are impressive. They give a good parts list too.

http://www.carcraft.com/techarticles...cam_specs.html

This may be a stupid question, but if you haven't either go the new headers or have not installed them, why not send them back to Summit so you get the right ones for your app. I have always found Summit to be very accomodating even when it's been my stupid mistake and not theirs.

They are already on the truck. Unfurtunately, I put them on before I found out that I really needed larger ones. My stupidity, so my loss.

OK, Jeff has PM'd me and is still working through a combination for his grunt motor. Since there is insufficient space to answer on PM (PITA 1000 character limit), I'll post my answer here on the original thread.

Since I can't seem to get Jeff up off the dime to get the correct 1 5/8 or 1 3/4 headers, we'll work with what he has.

Jeff, I would resist the purchase of the Summit intake/carb combination simply because of the manifold. Nothing wrong with a 600 CFM carb for your application, but the low-rise intake they're offering won't cut it. You need to uncork the intake and exhaust to let the motor breathe and the correct intake is an Edelbrock Performer RPM dual-plane, high-rise. Think of it as a Z28 intake. They should never have used "RPM" in the name because this manifold (and others like it) will make more power and torque from idle to 6000 than any other dual-plane intake. Don't like Edelbrock? Fine, use a Weiand Stealth or Professional Products Typhoon. I've seen 7101 (square bore carb) Edelbrocks all over ebay (Ebay Stores) and other places for $149.95. There are also several offerings on ebay right now for used 7101's for a hunnert bucks or less.

For a carb, I'd use the Edelbrock 1405, 600 CFM, manual choke. Never did like automatic chokes, I want to know what the carb is doing at all times. Mount a micro-switch on the choke arm and run it to a small dash light to remind you the choke's on. Here's an offering from the Carb Shop with 2 days left on it. I'd bid a hunnert bucks on it. Item number: 130299766404. Don't like this one, OK, call the Carb Shop and order up whatever you want. Nothing wrong with a rebuilt carb from a reputable rebuilder in my opinion. Then, order up this calibration kit from ebay Summit, Item number: 370179428001 so that you can tune the carb to a gnat's eyelash once you get the motor running and take some plug readings. The item says 1406, it will also fit a 1405. Use this tutorial to tune it.....
http://www.edelbrock.com/automotive_...ers_manual.pdf
I didn't link ebay because the management here doesn't like it and that's cool.

We're gonna use 9.7:1 SCR and the cam I originally suggested, installed advanced 2 degrees. RPM intake, 600 CFM.
http://www.compcams.com/Cam_Specs/Ca...x?csid=85&sb=0

RPM HP TQ
1000 54 284
1500 103 361
2000 147 385
2500 188 394
3000 241 422
3500 286 430
4000 319 419
4500 342 399
5000 348 365
5500 304 290
For you other guys out there building a grunt motor, this combination will make another 15 hp and 22 ft/lbs of torque with 1 5/8 headers.

Those numbers are PERFECT! I will stick with the Edelbrock 7101. I will find one either on ebay or craigs list. As far as the carburetor goes, I am going with a new one. Don't know which one yet, but a new 600 CFM. I will also use the 12-238-2 cam.

The only thing that could really be a fly in the ointment is that the 882 heads on this 1974 2 barrel 350 truck could possibly be 1.72 intake valves. At least that is what some articles that I read say. Most likely they are 1.94, but if they aren't, then I will have to find some that will work.

Hey techinspector1, what version of Dynosim are you using?

Jeff

Hi jbright300,
I wish we had rust free trucks in the Northeast like you guys have. I would love to build a 60-70's pickup without rust.
I sell balanced stroker kits that I would prefer to use a 4 bolt main block (although 2 bolt mains will still work, just not as strong), stock reconditioned heads or RHS Pro Torker heads, or Edelbrock or... The combo needs to match your driving style & needs. Don't build a high reving monster when towing is what you're really looking for.
I guess the first thing you need to concider is your budget. The MOST important part in this build would be a good overdrive 5-speed. Tremec has truck 5-speed for about $1500.00 new. With this you can tow and get mileage without an automatic transmission failure.
Call me if you want to go over a parts list & your budget.

I have had my fill of automatic O/D transmissions. And I don't want a standard.(The wife will be driving it also). This time I am doing it right....
TH400! Since you don't normally tow in O/D, why would I need one? This truck will never be a daily driver and will only be used to tow my travel trailer and an occasional trip to Home depot. It might get 1000 miles a year put on it. So for me, the cheapest alternative is just to do a TH400 change over since it has a TH350. My transmission guy even tells me he can build the
TH350 almost as strong as the 400, but I don't want to find out he was wrong on a cross country trip to BFE someday.

Quote:

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Originally Posted by jbright300

Hey techinspector1, what version of Dynosim are you using?

Jeff

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DynoSim Advanced Engine Simulation Version 4.20 with ProTools. There is a new version of this one out now, the 5.0 with ProTools.

This software comes with 800 cam files in it. There is a separate cam file you can buy for $49.95 that has 6000 cam files. If I had it to do over again, I'd get the 5.0 and the larger cam file. Total $150.

Bought an Edelbrock 7101 Performer RPM on ebay for $71.00!

Quote:

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Originally Posted by jbright300

Bought an Edelbrock 7101 Performer RPM on ebay for $71.00!

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Score!!:3dSMILE:

Are the pro comp roller rockers any good?

1.5 3/8" CHEVY SBC PERFORMANCE ALUMINUM ROLLER ROCKERS

Ebay item 170323279475. They sure are cheap.

Quote:

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Originally Posted by jbright300

Are the pro comp roller rockers any good?

1.5 3/8" CHEVY SBC PERFORMANCE ALUMINUM ROLLER ROCKERS

Ebay item 170323279475. They sure are cheap.

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Hi Jeff, yeah, they're cheap because they're manufactured in mainland China. Some of this offshore stuff is ok and some of it is not. Personally, I'd bid on this set of used Scorpions before I'd buy anything ProComp.....Scorpion is a premium product.....
Item number: 120408708198

Hey Tech What my 383 pull it got Stock TBI head with 190 In
200 Ex @ .050 .475 lift at 8.7 comp. Stock TBI intake and Stock Exhaust, Thank you.

Quote:

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Originally Posted by Racecar100

Hey Tech What my 383 pull it got Stock TBI head with 190 In
200 Ex @ .050 .475 lift at 8.7 comp. Stock TBI intake and Stock Exhaust, Thank you.

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Yeah, I can do that for you, but the DynoSim requires some specific information in order to compute intelligently. If you could supply me with the flow figures on the heads, the CFM rating of the TBI and the opening and closing points of the intake and exhaust lobes of the camshaft, along with the theoretical lift of the intake and exhaust, I'll be glad to help you out.

Any chance you could run my Nova engine on the Dynosim?

1971 350, 2 bolt main, bored .030 over
TRW forged flat top pistons, 2 valve reliefs
882 heads 1.94 valves 3 angle valve job
Crane roller rockers
Comp Cams XE268H hydrailic cam
Edelbrock Performer RPM manifold
Edelbrock 750 carb.
MSD 6A ignition
Sanderson "Shortie" headers
stock Nova oil pump

If you need any more info, let me know.

Thanks

Jeff

727 in the cylinder, 76 in the head, 4 in the deck @ 0.020" piston deck height, 6 in the piston, 9 in the gasket, 8.65:1 static compression ratio.

RPM HP TQ
1000 40 212
1500 84 293
2000 123 324
2500 159 334
3000 211 370
3500 260 390
4000 298 391
4500 328 383
5000 356 374
5500 359 342
6000 346 303

Tech with all this info and #'s You Have . I sure would Love to see you build an Engine and Run it on Line For us ?

Wow, those numbers are EXACTLY what the guy at the machine shop estimated the HP numbers would be when I was building this motor! All this in a 2700 lb. car makes it a blast to drive. Thanks!

Jeff

Well, I'm FINALLY ready to start my 383 project. Unfortunately, the money just isn't there to build my 383 this year, so I decided to put all of the same parts I was going to use on the stroker motor into the 350 that is in it. I pulled out the stock 1974 2 barrel, 175 HP 350 motor that has 56,000 miles on it and pulled it down to the short block. Confirmed that it is a 4-bolt main. I could still see some factory hone marks in the stock cylinders and decided to leave it alone for now. I pulled a couple of rod bearing caps and main bearing caps and found the mains to be good. The rod bearings looked somewhat bad, so I replaced them. I bought a new Melling stock oil pump and put in a steel oil pump rod. I put the Comp Cams 12-238-2 RV cam in 2 degrees advanced. I found a set of 1971 LT1 487 casting number heads on Craig's list and put all new springs, guides, seats, retainers, and keepers in them. I had the machine shop do some basic port work in the bowls and shave off .020. I am using an Edelbrock Performer RPM intake and a 600 Holley carb. I couldn't afford a set of name brand roller rockers, so I am going to try out the cheap Chinese ones I got on ebay for $100(Cringe).

My Desktop Dyno says 332 HP and 431 lbs. of torque at the engine. Not the most impressive numbers, but it it a huge improvement over the stock. The low compression is not helping the numbers, but I won't have to buy premium gas all of the time.

I ran the engine on the engine stand for a couple of minutes just to make sure everything is working correctly and it runs great! It has 50 lbs. of oil pressure at idle and a noticeable lope.

Biggest thing about your build to pull your travel trailer---1/2 ton pickup doesn't have brakes, springs , load carrying capacity ----