Originally posted by kapp714x4fe
Well, turns out my 390 is a 410. Perhaps why I was so happy with it. When I first bought the truck I was told it had a 390. Suppose the joke is on him.
Shortly after buying the rig, I swapped out the stock heads and intake 2bbl (not sure what they were) for a set of rebuilt C8AE-H heads and edelbrock performer intake. Also Edelbrock (carter) 750 carb, headers, dual 2 1/2" exhaust. It ran very well for 2 years but now smokes very bad. Bottom end never rebuilt w/ stock cam (dont know what it is)
I would like to rebuild stronger. Going to bore +30 and keep 1U crank for a 416 I believe. What comp. ratio should I look for. Suggestions on pistons? Would a performer RPM intake be advantageous or will it exceed my RPM range for a higher torque motor. Also heard a higher lift/shorter duration cam would yield best torque. Is this true?
Thanks, kapp
Kapp, does it smoke all the time, or on start-up? My 428 smoked on start-up, but it quit smoking as it ran, and it turned out to be the valve stem seals. That was in about 1977...

Really great about the crank! It's good material, and the C8AH-H heads could be pretty good. They made a number of varieties on that casting - send me a private message or email or something and I'll look at what I've got on 'em when I get home.

Don't do too much (any) port work on the heads if you want bottom-end torque. The heads flow pretty well to start with (though I understand there's some machining you can do to make them flow well without opening them to the point that they have to flow lots of air - to do with the Thermactor connections if memory serves).

As far as cam, I'd have to look. The ones I listed above are largely compatible with the 390GT and 428CJ (same cam). The Lunati was the closest match.

Sounds like we're working on similar projects, though I want mine to lope and work as a drag racer, so I'm working on the 2500-6500 RPM range, C-6, and so on. I'll probably go with the Comp Cams version - if I'm remembering right, it was better for higher RPM.

Like Tech talks about, you can get more through the motor than the formulas tell you (even the ones on the Holley website). But you're probably looking for no more than 5000RPM, so the 750 would likely work well. I'm running the stock 735 on the 428CJ, and it pulls good into the 5800 range, so 750 gives you some headroom. (Don't have the formulas with me - I'm using my business PC, sitting in a hotel room in Dallas, trying to get tired enough to sleep).

I look forward to seeing what comes of this.