hey i just downloaded an engine compression ratio calculator from fordstrokers.com and put in 408w, 4.030 bore, 4.000" stroke, 6.125" rods, 212cc comb. chamber (as refered by some of you), .04" gasket, 4.030" gasket diameter and flattop pistons and got a CR of only 4.8:1
i was looking for something more in the 10-11.5 range, and by adjusting the combustion chamer size i found that the only way to do that is to get a 70-85 cc combustion chamber... is this thing wrong, did i put something in wrong, or am i just ****ed for compression?

 

212CC ??? [sm=alcoholic.gif][sm=icon_rofl.gif] Who the f*ck told you that ?!? LoL Thats WAAAAAAAAAAAAAAAAAAAAAAAY wrong. 70cc sounds more like it... that sounds toobig though... depending on pistons, gaskets, etc. try something smaller.

 

hahaha thats y try typing in 58

 

yeahhhhhhhhhhhi****edup lol... thanks guys[sm=icon_quiet.gif]

 

you have to add cc's for the reliefs in the piston to get a TRUE guesstimation

 

okay next question... now its too high
http://www.camshaftinnovations.com/SBF212.htm
those are the heads im lookin at
i used the 65cc chamber and changed the bore to 4.060" cause thats what those heads are made in and now i have a 12.5:1 ratio... am i going to be able to feed it pump gas?

 

flat top with a 62cc will put you close in your range

 

most aftermarket heads are between 58 and 64 cc's

your fine

 

does that mean fine to run pump gas with a 12.5:1 ?

 

No, you wont be able to run 12.5:1 on pump gas. The maximum compression ratio you can run will be determined by your total combination. Not only do you need to know your bore, stroke, rod length and the heads you'll be using,you'll also need to know which camshaft. Once you know these things then any experienced engine builder could recommend the best compression ratio for your combo.