340 w-2 crank

Getting hard to find them, they're all 8 bolt flange IIRC. You see 3.51" and 3.55 cranks sometimes, I had a 341" 318 that used the 3.51 with an off the shelf 6" MP aluminum rod and a KB hyper piston right off the shelf.

I was thinking about offset grinding a 3.31 crank to about 3.43-ish using a 2.00" rod journal rod but you'd need a .927" pin. I have a set of 6.125 x 2.00 rods if you were interested, i actually think it's a better way to go plus get a lighter bobweight, those old MP cranks are heavy.