Hi everyone. I’m new to all of this sort of. I’m familiar with the wrenching aspects of engine work but not the technical specs and things. I have a 1970 Pontiac 400 YD. #16 heads small valve 1.96/1.66 with the 254 cam that is pushing 290 horse stock. From what I can figure out. It has a torker 2 intake on it for some reason aftermarket heads and edelbrock carburetor. I believe 750 cfm. I was wondering if it is worth the money to open up the 16 heads to 2.11/1.77 or get so # 62 bare heads I can pick up. Trying to get close to 400 horse. Was planning on the summit 2801 cam lifter set too. Just wondering what people think. Thanks Al
Since the engine is newer then what the HAMB likes, send me a PM, my dad, Jim Hand and I, have built a lot of Pontiac engines over the years. But, as general rule, all the normal Pontiac heads flowed about the same CFM in stock form, the only real advantage to swapping heads is to gain compression. The exhaust valve size is not the restriction, the port is, so unless you do port work, increasing the valve diameter isn't going to do much. And, yes, we have a flow bench and have tested a bunch of heads. Loose the Torque intake!
Pontiacs are torque motors, don't try to build it like a sbc. Get the Jim Hand book. And the distributor rotates CCW!
"All the normal Pontiac heads flowed about the same" is an incorrect statement. There were low compression , 2 barrel engines that required smaller exhaust and intake port/ lower combustion/ heads. The GTO, Firebird, Grand Prix used heads that flowed significantly more. Al69fire - I you would like, I can provide you with a list of factory heads , cams, carburetion that will get you where you want to be. Its relatively easy to make 400HP out of a 400. Lastly, its good that you have an early generation 400, as the later years were weaker.
I'm a little confused...does the engine have the #16 heads on it now, or the aftermarket heads? If so, what heads are they?
Not trying to be argumentative at all, but this is also some verification as to what Joe Hand is referring to. This section is from a well respected author, drag racer, and Pontiac tester's book. "My extensive flow bench tests indicate that all 2.11 intake valve D port stock Pontiac heads have peak airflow that ranges from 200 to 212. The lower compression heads from 1971 to 1975 tend to be on the low side of the average, while the 6X was totally redesigned and the intake posts flows as well in stock form as any D port. So in evaluating and selecting heads, the prime concerns are these: * Combustion chamber volume * 2.11 intake valves * Screw-in rocker studs * Functional condition of the heads - how many valve jobs have they had? * Physical condition - no cracks or excessive dings or chips."
Contact Joe Hand as he suggsested in post 2. His dad has been one of the Pontiac Gurus since way before way back when. Side note Change your avatar from the bird to anything that might be HAMB friendly including a photo of your dog. This board is for 1964 and earlier traditonal cars only. Loose the orange thing from the avatar and put up a photo that won't get the moderators in an uproar. The engine has a carb, it isn't that much different from earlier Pontiac V8 engines but the car will get you a slap up against the side of the head and possibly a boot off the board.
the flow rating between all 72cc non r/a heads are nearly identical. the last time i looked into it, there was a 4 cfm flow @ .600 between the 62's and the big valve 16's as joe said, the port is the restriction. even with this restriction and the small valve 16 with the right cam, you can obtain the numbers youre looking for. i feel as if the 2801 cam is way too small, ditch the thinking of going to summit for a cam. spend the money and call a professional for a custom grind. im running a schneidr solid flat tappet 292I 302E with a .550 in a 400 with big valve 16's she ****sngets. as i dont know your set up, i would highly recommend ditching that edeljunk. they have decent street manors, but a few brodies will lean it out. if you can get a q-jet built properly, by someone that knows what their doing, they are great. but most dont know the tricks of that dinosaur. im running a quick fuel hr series. torquer intake isnt bad, but you might be happier with a dual plane like a RPM performer. but lets be real, were talking about 400 hp. not very hard to obtain with a factory rotating ***embly and cast heads.
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