what should the piston-to-head clearence be?

Hello all, I'm just about to put the heads on the block when I noticed that the piston is sticking up above the deck surface a good .020, gaskets measure .065 out of the box(uncrushed). Thats going to leave about .035-.045 piston to head clearence. Also any advice on getting the motor back into the truck, when I pulled it out I took the heads off first and then the short block with out pulling the tranny or transfer case. Can I install it w/ the heads on or not?