ok so i just decided to build a 408 instead of a 370..... now what else am i going to need besides a crank... does the block need any extra machinging besides the norm and a bore? also what pistons should i get... have 61cc lg stage 2 heads 2.02/1.60 and would like to use a factory head gasket... i know i am going to need a dished piston probably with valve reliefs but how much ? i dont want crazy compression but would like to keep it at like 11 ish under 11.5 and always run 93

 

http://www.rbracing-rsr.com/compstaticcalc.html

Use about -.010 for deck height, "10 out of the hole", which is about normal. 4.03 bore, 4.0 stroke.

With a .055 gasket and 61cc heads, you'd need 13cc piston for 11:1 and 9cc for 11.5:1.

 

so it looks like a -12 cc piston would be great.it really depends on your cam, you could easily have spark knock at 11:0 with a small cam but not have any at 12:0 with a big one.do you have a cam in mind yet or is that still undecided ? there is nothing wrong with 11:5 or more if your dcr is still manageable,even in a pretty hot climate.

 

i already have an ms4 was in my ls1 when it let lose so i dont know what the dcr would be with that one and all that jaz