cam has nothing to do with CR, specs like bore diameter, gasket bore,stroke, rod length, gasket & deck thickness, cc heads, type pistons, valve reliefs. thers a lot more than peolpe think

 

ok..... 351w, bored .60 over, 5.954 H beam rods, heads are 64 cc's, pistons are custom Ross flat top pistons cut for oversized valves, only 2 relifs in the pistons, gasket is .042 thick and has a 4.090 bore, deck height is 9.480

 

well not doing your compression height, id say about 10.9:1, like joe said, but if my math is right with your compression height, im gonna say about 9:1

 

Is the 5.954 rod length correct?

If so, the is one hell of a large cubic inch engine.

My calculations with a 5.954 rod bring it in at just over 616 cubic inches with a compression ratio of around 16.9-1.


Are my figures off or something? Someone tell me they are.

 

yea you must have put the 5.954 for the stroke. stroke is 3.50

 

I figured I had something wrong.

I didn't see where he had the rod length listed as 3.50, all I saw was "5.954 H beam rods".

What a jackass I am.

Using the new numbers, I come up with 10.2-1 or somewhere close to that.

 

*back away from the computer*
he didnt list the rod length 3.50. i put 3.50 cuz thats a stock stroke for 351w.(crank)

 

You're right. You're right.

I don't know what I was thinking. I spin myself out some times. Wasn't the first time and won't be the last. Too many hours looking at the computer screen after too many hours at the shop.

 

ok with a 10ish CR is it safe to run 93?

 

yes, just keep the timing backed out of it if you're closer to 11:1 than 10:1 (plus to give yourself a cushion in case you get some bad gas).