offset grinding the crank to 3.90 (2.20 rod pin) stroke works great with a 6.7" rod and 1.32CH if I'm not mistaken, or atleast the math works great.

the thing that keeps me hesitant from the doing the same with a crank I have sitting around, is that the rods I've seen are chevy width on the big end. the rod side clearance is large.

for ~ $750 you can buy a crank that is designed to work with the chevy rods...