This just got me thinking and so I called up my friend with the crate motor that is supposed to be a 380 he said it does have the R/T heads so I informed him it is a 390 hp motor. Also he measured the pistons for me and they are .069 down and I measured a stock 5.9 here at my house and the pistons are .071 down and I can promise you the soapdish in my pistons are bigger than the 2 valve releifs in his pistons but he don't have a CC measureing device so I can not give you a number.

Also not that it matters to this discussion very much but the valve springs on his heads are cylinderical not behive.