Thread: My Small Block Project

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Hey I've got some questions for you pros! I'm not a total car whiz, but just picked up a '67 Camaro with a 350 4 Bolt Main. I just received the block back from the machine shop, where it was bored .040 over. I bought the generic engine rebuild kit off of Summitt that has the Speed Pro pistons(expected compression is 9.72). I also bought a Comp Hydraulic Cam with lifters which has .525/.525 lift, with 110 lobe separation.

I don't know much about the setup (my buddy is guiding me), but what heads do you think I need to run to match what is already going to be installed? Anyone know what kind of h.p. I'd run with selected heads. I'm looking for 2.02-1.60 w/ 64cc combustion chamber and 200cc intake runners.

Any advice would be greatly appreciated.

that's an awful big cam, gonna come in around 2,500 and leave around 7,000, you may not have the static compression to run it ither, give us the rest of the specs, that cam may slow u down

Is this for the street? What kind of trans? What are you setting your squish at? There are a number of companies making aftermarket heads to match those numbers.....

Yes this is for the street, at least that's what I want it to be. I'm not the one building the engine, I'm more of the guy who buys the parts for the person whose building the engine. I don't know which numbers you need, but I'll tell you what I've been told by my buddy. I have a TH350 Automatic, that we are going to put a 3000 Stahl Converter on. I'm going to get an Edelbrock RPM Air Gap setup, and have a Holly 4-barrel carb(unsure of size). Let me know which specs you need, and I'll get them for you a.s.a.p.! Thanks for the help!

What's the rest of the cam specs? Duration, both adv. and at .050 is what you need. And the c/r is determined by the pistons and head chamber size, along with a couple other things, so if you dont know what heads you're using, how can you know the 9.7 c/r?? Do you mean that's where you WANT to be?? Post the rest of the cam specs here, and the specific model number....that does sound big just based on the lift. You dont want a big cam in a street car, it sounds nasty, but will dissapoint you performance wise.

It's a COMP Cam Part #12-214-4. Duration @.050 is 253/253. Lobe lift is
.350/.350 and Lobe Separation is 110. Hope this helps.

Originally Posted by 67CamaroProject

Anyone know what kind of h.p.

Almost 400 HP (attached). I used 72cc heads to get near the Compression Ratio you mentioned. You may be able to get near that with a dish piston and 64cc heads. You should play around with a compression ratio calculator and measure during assembly to make sure you do not go any higher (unless you want to goto a aluminum head or run race gas).

Nice power on the dyno sheet. I still think that cam is too big in duration for what you're building. No offense meant to your builder, but I think I would call a cam company (comp or any other) and talk to a tech about it. I think for your c/r and intended use, you might be over cammed. Lets see what others say. I would go for something in the 240/246 duration at .050, and I personally would also go with a dual pattern cam, not a single like you have. Too big of a cam will kill your bottom end, and that's what you will feel the most on the street. I would hate to see you dissapointed after all this work. The RPM intake will be great, and a vacuum secondary carb will give you better performance on the street. Use a vacuum advance on the distributor as well. The Holley Street Avenger series carbs are getting very nice reports...a 670 would be nice on your combo.

Thanks for the info. I talked to my buddy and he told me that's the same cam he has in his engine right now with fuelie heads on it and he's pulling 12's in the 1/4 with his chevelle. Grant it, I want this car for more of a steet car than a strip car, so I'm kinda concerned that he might be traveling down a different route than what I had planned. We were talking about heads, and he suggested getting aluminum heads. Like I said earlier, I don't know all the ins and outs of engine building, but how much difference are the Brodix IK200 or Dart Pro 1's going to be in comparison to the cast World Product Sportsman 2's? I mean is there going to be a large difference between aluminum and cast, or between the different manufactures that I'd be able to notice on the street? Once again, thanks for all the advice

Basically, aluminum transports heat out of your engine faster than iron will. If you're running high RPMs constantly then that's OK, but if you keep in the lower REVs, as you will be most of the time in a street car, then you need the heat to expand the gas in the cylinder, after all, that's where your power comes from. I would go with Dart or World Product Sportsman Aluminum heads. They're quite cheap and as good as you will ever need on the street. Apart from the fact that alum heads can kill low end and are much more expensive aluminum and iron have different heat-expansion rates, so your choice of head gaskets, head torqueing and cooling issues will become more critical. And a 3000 stall converter will shake your bones at every stop light I'd go for a smaller one personally in a street car. For the strip 3000 or higher is OK, but if your cam comes in at 2500 and the converter at 3000 you'll need new tyres every other month. I would also go for a slightly smaller cam, a cam that big in a street car will get you some wear problems before long
As always, that's just my opinion...
Hope I could help,
mad

The car will flat run with Brodix IK180cc heads and a Voodoo 276 camshaft. Leave the compression at 10.2:1 and set piston to head clearance at .036"-.040" for proper quench area. Go with everything else as planned and a 3.73 gear. Be ready to run low 12's and with good traction maybe through some Caltrac bars you'll see 11's.

Mad Max

I have a question about what you said regarding the heads. You stated that the aluminum heads are better when running at high R.P.M.'s, and the cast are better for lower RPM's. You then explained that the cast would keep the heat in, and allow for better burning due to the retained heat in the cast heads. After that you suggested the Aluminum Style heads??? You lost me there... from the way you made it sound, I should buy the cast heads, not the aluminum heads. Correct!??

Sorry, my error. I meant go for iron heads:
Either World Products Sportsman II or Dart Iron Eagle. Or just get a set of stock L31 Vortec heads (don't know whether you can get an airgap for them) or get some 492 or 186/041-style stock heads and port them out a litte in the bowls. Then go for a STREET cam. I'm sorry, but the cam you have won't be fun at all in a street car. Comp-Cams say it's a drag racing cam, and that's exactly what it is. Comes in at about 3500 RPM, mostly you don't even see that type of RPM in regular street driving. Except when passing maybe. Under 3000 you're going to get virtually no power at all, because of the huge overlap of this cam. It'll kill every head you put onto it except for real racing. Get a shorter one with less lift, or you'll be buying a new valve train every other month
I'm not trying to disillusion you, I just hate to see people giving up because things don't turn out the way they should... And that cam won't turn out the way it should. Also a 3000 Converter is too lose. Go for 2200 for stoplight performance, depending on rear gears. If you have any more questions, feel free to ask, we'll do our best at answering them.

Hope I didn't shock you,
Max

@rhamm1320: please run this test with all other things equal, but other heads, like some Brodix or something. Dial in 220cc, 64cc (C/R should be around 10.3 at least for this cam) and race fuel. Just want to know whether this setup would reach 500 HP or more, the cam should be capable of it, which would be a sure sign that it's not working efficiently in this engine if it "only" produces 400 HP...

Mad Max...

Thanks for the quick reply. Now all I have to do is to try and figure out which cam to put in. Like I said earlier, I'm in no means a mechanic or an engine builder, but I do want as much power and run-ability out of my setup as possible. I appreciate all your help, and am looking into the cast heads. Let me know if you have a cam selection that you think would be a good match.

Thanks!

OK, I think some on this page might object but here's a few points where to start.
1) Start with an idea of exactly what you want to do with this vehicle. If it's sunday fun driver and you want good sound you'll need different parts from if you need your car to run every single day and just want a bit of fun at the weekends.
2) Remeber, you can only chose two of the following: good - fast - cheap.
3) Buy iron heads, closed chamber, not over 64 cc chamber, not over 200cc intake runner volume. Big valves are OK, but not a must, as you might get bad shrouding and thus get less flow than with small valves depending on the exact casting.
4) Get your powerband down low and make it nice and wide. Build for intake speed, not only for amount
5) don't go over 650 cfm on the carb, but get a good one which you can tune nicely (Holley's are a bit fiddly sometimes, but a good book will help. Edelbrocks are more or less foolproof)
6) flat top pistons, try not to exceed about 10:1 static CR, with nice quench you'll be running safe on pump gas until 10:1.
7) When you've got a good idea of what you want the engine to do call as many cam manufacturers as you can find and get their advice. I'm by no means expert enough to say what cam you need for your purpose. Then when you have the specs from as many companies as possible find a suitable compromise in specs and get one within these specs which fits in your price range. The cam manufacturers are experts and if you find a compromise between 3 or 4 manufacturers that'll keep you on the safe side.
8) don't rush anything.
Wish you a lot of fun with your build and as always, all questions are very welcome!
Greetz,
Mad