Dan and I pulled the 455 out of the '70 Lemans and noticed the oil pan was rocking on the crossmember and the center-link was rubbing against it too. There were corresponding 'rub' marks on the oil pan too! I'm so glad we are swapping motors between three cars otherwise I would have never known about this...I wonder how long before the center-link wore a hole in through the oil pan!
Obviously, the new motor mounts I bought are crap and compress too much and don't resist any motor rocking. I wonder if our hosts Mighty Mounts ( $100) would do any better than the standard $20 ones we used. We didn't notice any damage to the crossmember at all. I recall someone was fabricating 1/4" steel spacers to go between the crossmember and frame mounts, or we may have to fabricate our own if the mighty Mounts don't raise the engine any.
Dennis