Hi guys. I am looking to convert my th350 transmission to a bigger th400 for my 455. Will the floor shifter on the th400 fit correctly the console of my car as it was on the th350? Or any modification of the console should be done?

 

The shifter is bolted to the floor and nothing needs to move. Even the cable is the same.
What you do need to worry about is the parking brake cables because they mount to the crossmember. The cables are different lengths depending on the transmission due to the different mounting location of the crossmember.

 

I'll add that while the floor shifter and cable are the same for both transmissions, the bracket that bolts to the trans pan and holds the lower end of the cable IS different from the TH350 to the TH400 due to differences in the bolt spacing. This is another one of those things I learned the hard way years ago.

Repro brackets are readily available.