What are my options for bolting a different trans up to a slant 6 bellhousing?

Went to the local salvage, found a 64 slant 6 that has a 3spd manny tranny on it, getting the whole package. Was wondering what different transmissions could bolt up to this bellhousing. Also what kind of power can I put to the stock 3spd? It will have a blown 225 in front of it. Also, I have no clue about these trannies, this may sound like a stupid question....but how does one change it from a 3 on the tree to a floor shift? I have never seen one of these trannies and have no idea what the linkages look like, is it a toploader tranny or what? Thanx in advance
Author: admin