Speedpro H405 pistons, what to expect for performance?

lol that was me... we have the speedpro 285AP?? pistons in our 318...

easy enough to check compression...

how far is the slug in the hole
CC's of a chamber
head gasket dia and compressed thickness

plug that in with the other needed info and it spits a number at you

http://www.kb-silvolite.com/calc.php?action=comp