garagepunkfan -
Not knowing what the application of your GMC will be, I share the concerns of Panic and some of the others. You need to take a hard look at the rod to cam clearance. Even with a 4" stroke, the clearance is very tight. I assume that with the smaller 2.125 rod journal, the big end of the rod will be smaller than a stock GMC, but it may not be small enough for a 3/8" stroker.
Another concern would be the amount of overbore. If this is a street engine, I would be worried about overheating due to the thin cylinders. I have run 302's with up to .210 overbore in competition engines with the water jackets filled, but I wouldn't try it in a street engine.
The last thing I would question is if the tangs on the Chrysler bearings will be compatible with the Pontiac rods (I have no idea about this). Let us know how your project is progressing.
Bob
