I have a 72, 71 cast date, industrial 413 block I got from a local guy. It’s 4.23 bore with JE pistons. It’s supposed to be very thick and could go to 4.32. I just got a new Molnar 3.75 -2.2 crank and 6.76 2.2 Molnar rods, stealth heads, A&A max wedge intake and repro max ex manifolds. Only 421 cubes