piston question for a 472

[JAMES]

piston question on a 472 8:5-1 the 74 had true flat top pistons 1 is shot and needs to be replaced if i replace it with another 8:5-1 piston and its not the same style will it throw the compression off ?????? or will it be ok this motor is going on a friends boat and need fast fix but also needs to have good compression

 

[Anonymous]

The piston needs to have the same dome volume, compression height and be weight matched to be done right. Many moons ago it used to be common practice to cheat on circle track engines by puting a flat top in #1 cylinder and pop-ups in the other 7 because the tech guys used to check #1 for compression and displacement, and the engines always lived fine. Of course the pistons were weight matched though. So I'd be more concerned with the weight than the compression as long as it isn't too terribly far off. As far as weight goes, You'll probably be ok for a quick fix if the piston is no more than 20gs heavier or 40gs lighter than the one you're replacing...But don't tell anyone I told ya ok? LOL

Felber