I have a GT6+ engine and non-OD GT6 tranny that I plan on putting in my 1979 Spitfire this winter. I also have a complete Tranny with J-Type OD from a Spitfire. I would like to add the J-type OD to the GT6 tranny. Anyone do this before? What is involved? What would be a good Diff ratio to work with this combo? I think I have a 3:89 in the Spitfire with OD. Thanks, Mike Mack 79 Spitfire 73 Stag 80 TR8 76 TR7