T45 on a Slant Six
As far as I know the T-45 and the TR3650 that replaced it are Ford transmissions with integrated bells for the Modular motors from 1996 and up. It would take some work to make it work and its not a great trans to begin with. A T5 would be easier to start with and have more aftermarket support. At the end of the day you probably need to make an adapter since you wont find a slant bell to T5 bell housing.
Photo of T5 adapter and install - Slant Six Forum
TRANSMSSION DETAILS: TREMEC T-45 - Modern Driveline
What is your goal with the trans swap?