The Transmission in the 1600cc test car.(19,770 miles on the test kit.) The transmission in the test car was from a stock 1975 type1 with a  IRS 3.88 ring and pinion. Turbos like 3.88's  and big hills ( fat firends!!).The fwy flyer type gears are nice with turbo's. I like to use the solid nose mount and then run stock rubber rear mounts. As long as you have a good traction bar like the one from Low Bugget.com everthing will hold up just fine. Thats it, no big $ gear box for this setup!. I drove the car all year and made over 20 pases down the track.Now the more power you make the more you are going to ask from your gearbox. Dont be cheep when it comes to your gearbox!!