does anyone know what the stock piston dish volume and compression is for an 87 350 truck engine(TBI)? i'm starting to rebuild one but i don't know what i need to do to get about 9.5:1 with 58cc heads.

it looked like the deck was at least .060 or .080. if i had it decked, with 58cc pistons, and a .042" thick gasket what would the diston dish have to be?

 

Most stock pistons of that era had about 12cc worth of dish to them.

With that head gasket, .025 piston deck height (measure at the true top-not down in the dish), 12cc dished pistons (30-overbore, given that you are doing a complete rebuild), assuming 9.5cc for the .042" head gasket, and 58cc combustion chambers you will be at 9.58:1.

An alternative way to go would be to use pistons with an 18cc dish, .010 piston deck height and a thinner .028" GMPP head gasket (6.5cc). That would put you at an almost identical 9.6:1.

 

I've measured up to 14cc on 350 dished pistons with four valve reliefs and the beveled shoulder around the top ring land. 12 is a safe number for general argument's sake - not to start any arguments...