One piece rear main vs. two piece question

I have an LT1 which is of course the later one-piece rear main, externally balanced on the crank damper only. I have a flywheel for a two piece rear main sbc/bbc. What prevents me from using it on the LT1? The bolt patterns should be the same, both are a neutrally weighted flywheel. Shouldn't they be physically interchangeable with obvious exceptions to how its balanced?

um.... number of teeth on the flywheel?

sorry.... that was just the first thing that came off the top of my head, especially if the bolt patterns are the same and they fit the same type engine.
i am by no means an expert in this area.

This is a from an engine blueprinting book published by SA Design:

"In 1986, Chevrolet small-blck V-8s began to use a one-piece rear main seal and matching rear main cap in an effort to stop rear seal oil leaks. This required changing the rear crank journal, flywheel, and flexplate bolt pattern diameters, the oil pans, pan gaskets, and timing chain covers. Similar changes were made to chevy Gen. V and Gen VI 366, 427, 454, and 502 big-blocks in 1991 and 1996, respectively. Chevrolet and some aftermarket companies make rear seal adaptors that allow the use of early two-piece rear cranks in late model one-piece rear main seal block. Depending on which adaptor you choose, an oil pan designed for a one-piece or two-piece block cn be used. The rear seal adaptors are helpful if you have an expensive crank made for a two-piece seal and wish to use it in a one-piece seal-style block. The adaptors come with the required bolts, dowels, gaskets, and instructions concerning the drilling and tapping of holes to mount the oil seal adaptor."

Their mainly talking of using an early model crank in an late gen block, but it should have the information your looking for.

Oh... so they're different bolt patterns. I was mistaken :) Thanks.

....i recall something about them being bolted to different parts of the casing.....
not that is any use now...