Let's start out asking if this is going to be a daily driver? Have you had the block, crank, and heads to the machine shop yet? Are you using the heads that is on your motor? Using your 1993 GM heads will need some work, mild porting to get them to breathe better. The pistons you list with the 76cc heads will have a compression ratio of 11.3:1. Too much to run off pump gas. You need this set of pistons if using your 76 cc GM heads. Keith Black/KB Pistons KB106KTD-030 - Keith Black KB Performance Piston and Ring Kits - Overview - SummitRacing.com
or these http://www.summitracing.com/parts/UEM-9902HCKTM030/
Use a Fel-Pro 1094 .015 steel shim head gaskets (4.100 x .015) if your block has not been decked. This will give you a quench of .040 which is good for using pump gas. Your compression ratio will be around 9.1:1. The Scat rods are from China but are good rods. The top ring gap for the top and second ring should be .026. Unless you are doing a lot of heavy towing I would file them to .026. If you do decide to open the gap just do the top ring gap. I would also call Comp Cams to see what they suggest for your camshaft. I don't like the exhaust lift lower than the intake lift. Most stock heads need higher exhaust lift. I would suggest the Comp Cams K12-262-4, 218/224 duration, and 0.464/0.470 lift. I would call Comp Cams to get their opinion.