Rpm 340 Cyl heads on a 318 !

Sold most of it I have one more block and two cranks but they are at machine shop getting checked out .
Ok but why a 318 then instead? Dont missunderstand me here i like 318s but if you are going to do a good high powered smallblock the bigger bore is kind of a nice feature to have and having both options i would certainly have done a 340.