I know. The 383 I have is no slouch, either. I keep seeing on this forum everyone saying they'd never do it again. Once I cut the K-member for the conversion mounts, I'm committed to a big-block.
If you have a small block K member all you need to do is cut the front half of the motor mount Tower off so the oil pump clears. You could technically weld all that crap back on that you cut off