My uncle and I have a small-block Chevy 350ci and a big-block Chevy 454ci that we want to rebuild for possible use in a 1992 Firebird (if I decide to buy it). We we'll probably be rebuilding whichever one we pick over this winter and install it next spring in time for next summer. I'd possibly throw nitrous onto it a few months later, and hopefully a s/c by the next summer.

I was wondering what compression ratio I should be looking to target to be safe for both a supercharger (@ 8PSI or so?) and a 100-shot or so of nitrous. Is there a certain range for the piston doming I should look for too or would flat pistons work? The EFI system will be swapped out to carb along with getting rid of the rest of the computer.

Would something like an 8.5:1 be good for this type of setup? If I were to get 8.5:1 pistons right away for the engine build, would that be enough compression when running N/A (before I get the s/c and N2O installed) or would the car really dog it with such low compression?

 

id be shooting for 9.0 to 1 with a small chamber head.

adam

 

Alright, thanks, any other recommendations?

 

Would it be a roots style supercharger or a centrifigal style supercharger?

Here is a chart that ATI keeps on their website. 9:1 on 8psi with a roots blower is probably asking for detonation.

 

Centrifugal. I was looking at some ATI and Vortec setups IIRC. Looks like 8.5:1 CR would be best for up to 10psi. How would this handle with nitrous though without an intercooler?

 

The chemical reaction that occurs running nitrous is supposed to cool the inake charge significantly, that is why companies like Nitrous Express make nitrous kits to plumb the intercooler. GMHTP used a 50 shot on one of their dyno cars for an added intercooling effect. I would get some other opinions on this board, but from what I have seen a small dose of nitrous shouldnt hurt anything as long as you are careful with your timing and plugs.