I wasn't even sure if these were still out there. This is my old (I mean old) web site. We put a Tremec in Dad's Nova probably 15 years ago. (It's a 3550, but should be the same size). It required some tunnel work to get it to fit. We left the 4-speed floor shape so that his carpet would still fit OK at the time.
http://www.wiedos.com/Nova/Nova%20Tremec.htm