534

534 is different engine. About 512 is as big as you can easily get to.
Max offset gring on 430/462 is .400. Reduce rod journels from 2.6 to 2.2. This will give stroke of 4.2, not the 4.4 of the 534. Some 430 blocks will go to 4.4 bore, virtually all will go .060 overbore. Oil galleys are fine, just upgrade the oil pump to an FE high pressure. 2.2 Rods are plentiful, shop around. Get close to a 7 inch rod. Pistons are expensive. There was a nice set in the forum about a year ago. My inquiries for a set of forged pistons, BBC wrist pins, BBC size rings, and deep valve reiefs was 1500 dollars. Your major challenge will be making a good intake manifold. I have seen pictures of fabricated manifolds, but that is beyond my abilities. TJR