Even though you've decided not to do it I need to add this for future readers of the thread.

You'll need to use the '49 bell housing because the mounts changed in '54.

For the front mount you'll just need to drill holes in the mounting flange. I was fortunate enough to have a spare to use to lay out the holes. Lacking that, after you get the old engine out measure the existing holes and lay them out from that. After drilling them round I squared them with a triangle file.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.