440 build help

71 I would guess either 906, or 346 castings. You can find the #'s by pulling a valve cover, it's the last 3 digits. Either head flows about the same, neither had hardened seats, but I wouldn't get too concerned over that. I think compression was down a little for '71, but still listed at 9.7:1. As for the converter, generally the smaller the unit, the higher the stall. Performance converters start at 11" and go down in size. If the engine is left stock, or nearly so, I think a 3,500+ rpm converter should work just fine.