BB issues

I have been told a couple of things recently and would like to get some facts. Question 1. Has anyone ever had issues with shock towers cracking due to having a big block.

Question 2. I have a 73 up spool mount K. Can you use a 400 with 76 Cordoba motor mounts. If so are there any issues to be aware of? Thanks guys.
1) Never seen that in my life. Been messin with cars since 1974. Not that that means a damn thing.

2) @Jim Lusk is your guy here. He can tell you what's up with the mounts and what will work with what. Super good dude. I tagged him, so he'll chime in.