Can you swap 915 output flanges

[Orange Crush]

I want to put a 74 915 in my 81SC. The output flanges to the CV's are different. Can I swap out my SC flanges to the early trans and use my axles? I have looked at a great chart someone posted on the BBS as to the different axle lengths, sizes and bolt patterns on the different years but none of the combos look like they work for this application. What do you guys think?

[Tom '74 911]

My '74 915 had coarse splined output flanges - the later 915s had fine splined flanges so my guess is no. There are a few threads on the different varieties of flanges, CVs and 915s etc... It's never quite that simple!

Who knows, you may get lucky and the diffs have been swapped or something so try it; it might work.

Tom

[Orange Crush]

Thanks Tom. Not the answer I was hoping for but, as you say, it's never that easy!

[Flat6pac]

Bruce

[CCM911]

Actually, I bought a 915 that was originally in an SC and put it in my 3.2. We made a notch for the crank sensors, and also had to change the axle flanges. This can definitely be done. The trick is to find the correct flanges. The splines are either coarse or fine, that is step one. Step two is to match to the correct CV bolt pattern. As far as I know, this can definitely be done.

[Peter Zimmermann]

Output flange splines are coarse through the end of 915/61 production in 1979, fine beginning with 1980, 915/63 production. A possible fix for you would be to see if you can put '74-type CV joints on the inboard ends of your SC axles.

[JeremyD]

Hey Pete - how difficult is it to change out the CV joints on the inboard ends?

Orange Crush is buying my transmission - and I will have the opposite issue - going from 1974 axels to a later 915 (1986)

From what I can gather - there are a few different sizes of flanges (100mm and 108mm) and there are a few different diameters of axels?