I have had almost a dozen different 2nd gen f-bodies,never owned a first gen,3rd or 4th. I'm debating what I want to build for a motor,the current 400 in it is tired (was rebuilt cheaply by last owner). My choices are: rebuild current 400,rebuild current 400 and turn it into a 455 w/small journal aftermarket crank,build my spare 502 or 540 bbc that I have majority of parts for in shop (which would be total sacrileage on a pontiac car). I have to decide soon as winter is coming and I want to have it ready for spring,Smitty