Do I need new driveshafts or not? Confused..

Bo · Bo's Garage

Upgrading my 911 from a 2-liter engine and 901 tranny to a 915 mated to a 3.0 liter.

Do I need to get newer driveshafts, or will the ones I have fit? Are there different sizes of these, or what gives?

I've heard conflicting theories on this, and don't want to spend more $$$ than I have to...

I might add that the driveshafts I have today are not of the earliest kind, but I can't really tell how old they are.

Anyone who's been through this procedure?

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1972 911S Targa
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My project!

Roland Kunz · 07-05-2001, 11:22 AM

Hello

Your 72 musst allready have a 915 trany with the 4+2 axles ( 4 bolts 2 pins ). So I´m a bit confused.

Grüsse

Joe Bob · Joe Bob's Garage

If you are worried about the horse power twisting the axles, don't. I ran a 250 hp 3.0 with a 901 trans and stock axles and CVs.

Just watch out on downshifts and burnouts....

Bo · Bo's Garage

No, my 72 did NOT

have a 915 tranny, for some reason... Along the years, someone put a 2-liter and a 901 in (!), which I'm now about to upgrade.
I'm not worried about if the axles will manage the hp, I'm worried about the actual physical fit, since I've heard from somewhere that different years of driveaxles have different lengts.
Can that be correct?

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1972 911S Targa
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My project!

GIBSON · GIBSON's Garage

Bo, If I remember correctly,the axle length is not the problem. Your SC 915 gearbox should have the 6 bolt flanges for the later cv joints. Your outboard flanges will be the large 4 bolt with 2 locating pins.
I've removed the drive flanges on the 915 without any problems but I've never switched them to earlier 4 bolt flanges. Maybe somebody on the board can tell you if that's a possibility. If not, you'll have to change the outboard flange to the 6 bolt
and you should be good to go. See what more informed members have to say, that's my take on it.

Bruce Herrmann
73911S

Roland Kunz · 07-06-2001, 02:41 PM

Hello

Need your exact Modell is it a 71 or a 72 ? was it a sportomatic ? Now you have the 6 bolt CV flanges ? How old is the 901 trany ? do you have the aluminium cover inside the trany CV flanges ? Or can you see a screw head in the center ?

Grüsse