the engine is a 350 out of a 84 vette. it curently has 76cc 462624 junkers.

 

As said in your other thread, need to know the pistons in the engine. Casting numbers, neither head nor block, will tell you that.

 

when i tear inot it i will post more info. thanks

 

There might be someone hanging around who knows more about those Vette CFI's than I do. It doesn't come up on this Board, though (to the best of my knowledge). Google didn't help much, other than to confirm the casting #'s you provided.

 

go into mortec.com and it will give you the casting #,s for the heads and blocks

 

crossfire84, i have a 350 from a 84 vette. are you familial with the engine? what pistons are stock, and whats the stoch comp ratio?

 

i found it... stock comp ratio for the 84 vette w/ CFI 350 was 9.0-1 w/ 76cc heads. what will my comp ratio be if i install 58cc LB9 heads? streetable? will i need to run regular or premium gas?

 

9:1 with 76cc heads means you'd have a set of flat tops, if you have the original ones still there. With the LB9 heads, your looking at around 11:1 CR or so if you keep them at 58cc. VERY borderline with even with pump premium, since they are cast iron heads, but it can be done depending on what cam you use. I had 11.25:1 CR with my 350 with 601s and it worked fairly well with pump premium and a very spot-on tune. I used the XE274 cam with that, and it seemed just right for that CR.

 

the cam is stock for the 84 vette

 

Then its the same as the L69 cam, if I remember correctly - you'll need something bigger with that much compression, or use different heads. L98 heads would be a good choice if you dont want to change the cam. They would bring it to right around 10:1.

 

well....i tore into the "350" today and the pistons are flat top w/ 4 valve relives, on each piston top the numbers .040 are stamped in?

 

oh! non stock then eh? Ok, check the deck height. (know how?) That's crucial, and you can easily find that out now.

You can port the LB9 heads and open up the chambers. That'll put you around 64cc. Then you're laughing. 350, 305 heads, T-10 eh? hmmm. Copycat!!

 

idk how to check the deck height?

 

Bring a piston up to TDC. With the piston crown and block deck already cleaned of carbon, gasket residue, etc., put a depth gage on the deck and the pin on the crown, measure the depth. If you don't have a depth gage, put a straight edge across the deck, use feeler gages to determine the depth.

If you don't have any of those tools, it's time to get them.

It's a good idea to measure at least the front and back cylinder of each bank to make sure there aren't any gross mis-machinings of the block decks.