I like the way you think. I always say that you can drive a fast car slow, but you can't drive a slow car fast. I was thinking along the lines of a P4876673AD siamese 48-degree R3 block, W2 heads, a solid roller and offset lifters, and a custom billet steel crank on alcohol. A 4.100 bore and a 3.750 crank yeilds 397"