Originally Posted by DrivingMissDD

From a Rod & Custom article;

The hemi UltraBell can be ordered to fit a TH350, TH400, or Powerglide. What you have to do next sounds like a "radical bell-ectomy" but taking off the stock bellhousing from your transmission shouldn't scare you. Complete details and measurements are included with the UltraBell kit, and the deed can be done with a Bridgeport, reciprocating saw or an air tool with a cutoff wheel. The bulk of the housing is taken off on the first pass, leaving a small amount for a die grinder to finish off for a nice, clean edge. The cut doesn't have to be perfect (just don't let the blade wander into the pan rail or top of the front pump).

You can mask off the front pump and input shaft with duct tape and plastic during this procedure, but there's no need to disassemble the whole enchilada. Once you've done the obligatory post-op cleanup, you can remove the front pump bolts, push the UltraBell over your trans, and bolt it down using the high-strength Allen bolts supplied.