Well, add me to the list of folks on the 400 "been there done that" list. Paid a bundle to get Ross to make the pistons, ran the 4V heads with screw in studs, reworked on the flow bench, etc. etc. It ran ok, but never what I wanted out of it. I would say you might want to take a look at the Ford M6010- blocks if block strength is a concern. My personal choice was an M6010-A58 out to 427 with Twisted Wedge heads with some flow bench time. Very, very strong chebbie killer!!!!!!