Spoke with the engine builder today. He's pretty sure the compression ratio is 8:1. He said there were only two choices for the pistons since we were just going with a stock piston, he was going to try and look them up tomorrow since I found his itemized bill. I'm fairly certain they are flat tops.
The date on the block is 4-11-78.
The Weiand intake is model # 8009, dual plane, with an Eddy 750 on top.
Camshaft is Direct Connection. duration 272, overlap 48, design lift @valve .455",

71GTX. Yes, I was reading that the heat range values for plugs differ with each brands and some are reverse of others.