MAXIMUM CRANK UNDERSIZE

In todays supply issues .030" under on the mains and .030" undear on the rods will probably be all that you'll find. 30-years ago you could have found .060" under for either journal. Worrying about the balance will be no issue. What you take off the crank you add back with the thicker bearing shell. If your still concerned just remember a 500" NHRA engine uses a 2.5" main journals/ 1.88" rod journals and turn almost 11,000 rpms. To many people get freaked out on under sized bearings. If you need more than .030" under to correct your problems I would try posting an wanted ad for whatever size you need to make it right, weld the crank back to standard, or get a different crank.

Tom