Check again on them Speed Pro Pistons . The only way you could get 10.5.1+ C/R is if you have the .125" domed Pistons with your 64 cc Heads . With Flat Top Pistons your Just over 9.5.1 C/R . Go with the EX262H camshaft . You will also need a 2800 Stall Speed . Or better yet a TH-350 and a stall speed . Your Corvette may have a 3.55 Gear stock .