Keep the Q Jet, it’s rated 750 cfm. Far better than a vacuum secondary Holley. If your hellbent on changing carbs, get an 850 double pumper.
You were right about the piston fit. .09 is pretty damn close (see pic). I will research the pistons you recommended. Bob
The pistons I mentioned are .090 below deck also but no dish which net 9.6 compression. 1.905 compression heigh. The factory pistons for 68-75 should be about.06 below deck. Valve clearance is not a problem at this height especially with the 460ish lift of the cam you have Or you can look for 340p piston which is the factory type 10 to 1 cast piston. It should net about 9.2 compression without block milling or the .020 thin heads gaskets. Pistons have a thin dish and set about.060 below deck. ta performance should have these 340 pistons. They only have .030 over. As far as I know there are no other oversizes available.
