Pony Motor bearings

Is what your looking for standard or undersize?

Its going to have to be undersized on the mains, but if I can get any part number for any size that will be a good start

Flywheel end crank 0.020 under is an 8B0006 RPB 4F9416
Other end 0.020 under is an 8B0005 RPB 4F9413

Thanks for the information. As it turns out the place in california says they can no longer get the main bearings. I have a lathe and mill so Im going to be making my own main bearings. Im going to just have the crank grinder cut the crank just until the journals are smooth again and then i will custom make each side of the bearing for a perfect fit. I was able to find to the rod bearings and piston rings so things are going pretty good.

6061-T6 aluminum seems to work well but don't make the clearances to tight.

Not sure if the 4T pony bearings are the same as the 3J ones (the 4B903 crankshaft part number is the same) but if they are, I just bought, from Caterpillar, one bearing for ~$90 and the other for ~$100. They're available at least for the 3J. My engine rebuilder estimated about $50 to $100 for custom bearings made from Oilite (bronze-ish) so for bought bearings, the OEM ones seem ok.
Cheers,
Neil.

Thanks for the info, I actually had ordered some 6061 aluminum. But I was actually thinking this weekend about maybe converting the pony motor to roller bearings on the main crank.