I see that Callies has a 4.250 inch stroke crankshaft on the shelf for the 340 block. Can anyone tell me what problems I might run into if I tried to install one of those into a 340 replacement block?

The crank comes with 2.10 SBC rod journals so I'd probably go with a 6.250 long SBC connecting rod. That leaves 1.205 for the compression height which is tight but I think it would work. The piston would need about 25 cc dish to keep the compression reasonable for pump gas.

I'm wondering about clearance in the bottom end and if the oil pump will fit and stuff like that. I know lots of guys use the 4.00 crank without any issues but I haven't seen much talk about the 4.250 crank.

Any input? Pictures would be great.