Mr Hoyt is correct.
I should have stated "original" (center) mounts for your application as; you don't have them on your Bell Housing. Bracing there (rear) is always better as he states.
If the center mounts (orginal) will fit, use them alone, like GM did.
I put a 55-235 from a passenger car (no center mounts) in a 53 passenger (both stick) and didn't have a bit or trouble. I can't recall if it (53) had the rear (bell housing) mounts. But I don't think so.
Are you speaking of the truck mount (front) which is in the center, under the crank?? I have always used the ones (L & R) of center, on the front plate.
