Help identifying cylinder heads

[donmcgowen]

Hi,
I have a set of heads that have been sitting around for about 15 years. I believe they are Dart II Sportsman heads, but the intake and exhaust castings are very rough. Doesn't seem like an aftermarket head would be this rough. Anyway, I'm going to port them. I just need to find out what heads they are to know if I want to use them or move on. They have 2.02/1.6 valves, triple valve springs with guides, 64cc chambers, at least they look 64 by the shape. Your help would be greatly appreciated.

https://www.dropbox.com/s/vv9pgg9cm3...51331.jpg?dl=0

https://www.dropbox.com/s/r5pvplsd4a...51431.jpg?dl=0

[techinspector1]

Anyway, I'm going to port them.

I have to smile to myself whenever someone says this. If you don't have a PhD in Fluid Dynamics or 30 years experience porting heads for a living, chances are pretty good that they'll flow less when you're through with them. Just like a woman's rear, it's all about the shape, not the size. For instance, the Chevy L31 Vortec heads are only 170 cc's on the intake runners, but they will outflow aftermarket heads with larger 180 and even 190 cc intake runners because of their SHAPE.

.

[donmcgowen]

I wasn't implying that "I" was going to port them. But if they are decent heads I will have them ported when I have the engine built. I'm just trying to figure out if these heads are worth building around.

Thanks.

[glennsexton]

I'd have them checked for cracks and then get a price to deck them, drill the steam holes (assuming this is for the 400 engine), valve grind, and new springs to handle that monster cam you're talking about in your other post. I think you'll find that these iron heads will not be satisfactory for c/r in the 11-12.5:1 range that the cam you're looking at requires. See the spec's at: CRANE 118131 SBC BILLET ROLLER CAM TR-242/3867-2S-6 $359.95 BUY ONLINE

In my humble opinion, you may want to rethink this build. These heads and the Crane 118131 cam in a 400 is just not a good combination.

[donmcgowen]

Thanks Glenn. That is helpful. So do you think I should go with a regular hydraulic flat tappet cam? Something around 232 duration with .510" lift? If I did this, I probably wouldn't need to clearance the rod bolts. It's been years since I worked on this motor, but last time I installed the pistons, the rods were hitting the cam.

So I'm thinking that you believe these heads are not that great? If I were going to get the heads machined and a valve job and all that, I would probably just invest in some aluminum heads for $1100 or so. I don't want to invest much in these heads. I would get them cleaned but that's about it.

My other options was going with an already assembled 383 short block for $2200 and throw these heads on it. I think these should be good for 420hp with a cam, Performer RPM or Victor Jr. intake and a 750dp Demon carb. Just not sure if I want to invest in 400 with cast crank or just go with a pre assembled 383 short block for the $2000. The price might be around the same.

[Henry Rifle]

Just butting in here, but the next time I use a flat tappet cam will be . . . well . . . never.

[glennsexton]

Hey Don –

It appears to me that you’ve got a couple threads going here about a 400 build, some heads and a cam selection. It might be in your best interest to re-start this process and focus on one path to consolidate the information and let us help you. We really are a pretty intelligent group and the collective experience here is hundreds of years of engine building and hot rodding so the information you need is here, but not everyone reads all the posts so you’re running the risk of piece-meal responses. A couple suggestions:

1. Tell us what you’re building – is this for a car or a truck?
2. What do you want to accomplish? Will this be a daily driver or a weekend cruiser? Do you want to run this build down the drag strip now and again or just have enough punch to hold your own stoplight-to-stoplight? (Not an endorsement for street racing – but it is nice to dust a rice rocket now and again, eh??)
3. What’s your budget?
4. What’s your time frame?
5. What’s your skill set? Not meant to be condescending, but you need to be realistic about what you can do well. I’ve been doing this for almost fifty years and I still have some things that I defer to machine shops and those people who do precision work for a living. They have the equipment and knowledge and a good one is worth their weight in gold. I knew a lady machinist in southern California years ago and she was worth twice her weight in platinum!
6. Give us the basics on your vehicle, i.e., automatic or stick – what’s the rearend ratio – what size tires, and anything else you got.

Most importantly, you’ll need to build this thing on paper before you ever pick up a wrench. When we try and “build-what-we-got-laying-around” the results are marginal at best. That’s due largely to the fact that we gather “stuff” overtime that may (or may not) be compatible and remember that the technology in cams (in particular rollers) and heads has come a long way in the past ten to fifteen years. As has been eluded to in one of your posts, flat tappet cams are a real crap shoot and if not installed perfectly and run in correctly they will fail. Most here have had bad experiences with the removal of key oil additives to know that a roller may be more up front but saves money and heartache in the long run.

If you’re set on the 400 block it can be a great foundation as long as you understand Siamese cylinder design. Before you do anything, you need to have the block vetted by a reputable machine shop. Have it examined for any cracks and if it’s good, get it decked and have the main bearing bosses aligned bored to make sure everything is square. The 400 is known for running hot, but if the cooling system is properly designed it is not an issue. As such, knowing what you want to accomplish is again important. A boulevard beast that idles a lot is not a good fit for the 400 unless you have a large cooling system and use a well-engineered shroud and a mechanical fan with the stock GM clutch (think Monte Carlo – big car with a 400 and a well-designed cooling system but still notorious for overheating.)

The rotating assembly needs to be selected as a group, i.e., crank, pistons, rods and yes, the cam. Choosing the correct parts to install in a properly prepared block means you will not have to grind anything. I’m not a fan of trimming bolts and leave that to experts like Pat McCarthy as he has the tools, skills and experience to machine components and balance properly.

The heads you’ve been referencing are probably not worth the effort of a rebuild. I’d look to modern aluminum. I think I’d lean toward Airflow Research 195cc heads. As the name implies, they have 195cc runners and you can get them with a 65cc combustion chamber. If you want to err on the side of caution, get the upgraded springs from AFR (part # 8605) to eliminate any valve float issues. No matter which heads you choose, with a 400, they will have to be drilled to match up with the block's steam holes. Before you choose heads, you need know that anything much over 10:1 will give you fits in cast iron and compression over much over 10.5:1 – even in aluminum – requires careful matching with valve timing, i.e., cam selection.

Techinspector is the man to ask (nicely of course) to help you build your “stack-o-stuff” in order to determine your real compression ratio. Listen to him as he’s done this for a long time and if you don’t get this part right, everything (and I do mean everything) else will just not work as intended and you’ll be frustrated with the build. Make sure you get the deck height number from your machine shop as it is vital in this process. All small blocks start at 9.025” but after decking, that number will be less!

The cam should be roller – period. Lift and duration numbers should be a bit tamer than you’re looking at if you want to drive this thing on the street at all. And don’t look for a lumpy sound! It indicates poor design and equates to sub-par performance and says “I-wanna-be-a-badass” but in truth make one look, well – foolish to the knowledgeable hot rodder. I like sound as much as the next guy and am a big fan of 40 series Flowmasters, but not rough idle slop with raw gas running out the tail pipe.

Okay – I've gone on long enough. Hopefully I've not scared you away as we really do want to help, but let’s try again from a clean slate. Tell us what you’re building and we’ll go from the ground up with you.

Regards,
Glenn

[donmcgowen]

Thanks Glenn. I had separate threads because I figured I would separate the issues. Anyway, here goes.
1968 Camaro
Turbo 350 w/ B&M 3500 stall
4.11 rear

Motor - I bought the motor 15 years about when I was 20 years old. Now I'm older and have money I want to get the car done.
406
cast crank
5.7" rods - I would like to have ARP rod bolts and have them resized
flat top pistons - hoping for around 10.5/1 with the 64cc heads
Victor Jr. intake
750DP Demon carb
Hooker 1 3/4 headers

Basically, I want to use this motor to build off of. I want about 425-475hp for low 12 second times.
Where I'm stuck is the cam/head combo. I know the pics of the heads make them look like crap, but they seem to be
decent. By decent I mean 2.02/1.6 valves, 1.5 or 1.54 dual valve springs with damper, valve guides, rocker studs. I don't
think they are production heads because they have no casting numbers. I really want to figure out what heads they are.
I thought I remember the guys said they were old Dart II iron heads, but that's what I'm trying to figure out. Anyway,
they seem decent enough for now. Yes, I would like the AFR heads, but, I'm just trying to get a decent rebuild and get
the motor in the car. Once the short block is built, I can always upgrade the heads.

I do realize the cam is a bit aggressive. Again, I bought it when I was 20 years old and had this grand idea of the motor I was
going to build with no money. lol And roller cams are not cheap. I would hate not to use it. But again, if it's too aggressive for
this build, I will probably go with something like a Comp Cams 280 Magnum. Overall I think it should give me the 425-450 that
I want. Once I have the car running and driving, I will continue to upgrade the car as I go. But I don't have $5k to build a motor
with. I'm trying to use the 406 that I have and get it cleaned and assembled and then use the heads with a smaller cam for the
time being. I'm thinking if I went with a flat tappet cam, I wouldn't have the clearance issues with the rods that I have with the
bigger cam. But I may be wrong.

Just getting pricing from the machine shop they are really expensive. They want $240 to install the ARP rod bolts and resize the
rods. I could buy new rods with the bolts for that price. I live in the Chicago area and there are only 2 real machine shops in the area.
I'm trying to figure out if I build this 406 or just buy a 383 short block assembled and delivered to my door for $2100 from Summit
Racing. What do you guys think. I think this is a solid motor setup once I get the proper cam. But I definitely would like to hear your
opinions since I've never built a motor before.

[donmcgowen]

Well I have confirmed that my heads are in fact Dart II sportsman 64cc chambers and 200cc runners with 1.55 valve spring pockets. I think these heads are good for 420-450hp.