Installing the 89mm is a snap. There was an article in Custom Classic Trucks- Feb 2001, I think, where the author showed the install. Ignore the fact the guy thought it was a Dodge trans and get Chevy 89mm and you could do it in a few hours. I put one into my 46 and I had to change to a later bellhousing to get right bolt pattern and it still was fairly easy. Just make certain no problems with the external linkages. Shifts like a dream and hugely better than orig trans.
