915 tranny, late T3 car, big T4 engine, help!

[Wally]

Shad,
I cannot help you on all questions, but I have a 915 4 speed at hand from 3-'76. CV's of a type 2 cannot be used here unfortunately. Your 915/923 tranny will probably have the same dimensions. These CV's are about 110 mm outer diameter. Type 2 CV's are about 100 mm and bug CV's are 90 mm. Not a problem if the splines in the porsche CV's were VW like, but I heared they were not.
Michel Ghia said that you can use 914 stud axles (with 100 mm CV's so you can use type 2 CV's), but 'opening up' the tranny is not for the faint at hart. To boot, a porsche mechanic said to me that the stub axles of a 914 trans and a 915 trans are NOT interchangeble !?
Although I haven't done the mod myself yet, I understood that can can have drive axles made for you at reasonable cost, so one side would accept porsche splines and the other end would use VW splines. Ans you can than have them in any desired length.

The relatively (1 inch or so I believe) small change in transmission placement is not a problem. as I found out. I have placed a standard box 1 inch forward as an experiment to be able to use a porsche 911 engine. With a 2 ltr type 4 to it held out fine. The 911 engine never went on, because it wasn't approved of legally (should be 4 cylinders as stated in vehicle documentation). Would (just) have fitted though, but for the fan...

Good luck, keep us informed as I (we) are interested in your solution/choice.
Walter