Rear Drive Shafts For 914/6 conversion, Are 911 shafts stronger? Options

[ber914]

I am currently sorting out a 914/6 conversion which I bought and eventually hope to run about 250 RWHP in. One of the last items I need to tackle is the rear 5 lug conversion and am looking to put a set of correctly drilled 914 rear hubs on. However I have been told that the 914 driveshafts will be problematic with 250 HP. Would I be better off using an early (69 - 73) 911 setup of driveshafts, stub axles and hubs with an adaptor to mate the driveshafts to the 914 box? Would this be a stronger setup and is it possible to mate up with an adaptor?

Robert

[skline]

The shafts are not really any stronger, just shorter. Renegade makes adapters and PP sells them too. There are guys running V8's with more than 250 HP running stock axles and CV's. Its all in how much you want to spend. If you want to use adapters, try using Bus axles with the adapters. Much stronger than 914's.

[ber914]

Thanks Scott

Obviously not looking to spend money uneccesarily - just want to do things properly first time around. Was just going by what I was told by somebody with a similar car that he ripped up two sets of 914 driveshafts/CV's and then swapped to 911 shafts and CV's and has had no more problems.

Robert

[Qarl]

You want the '71 to '72 911 Drive shafts... Bolt right up. Are the correct length too! No spacer adapters necessary.

[ber914]

Thanks Karl - are they stronger than the original 914 ones?

Robert

[Qarl]

That's what my Race shop guy wants me to use...

There is one other issue that I forgot about... sorry.

If you use those 911 axles, then you also need the output flanges for the tranny.

What you need are the 915 tansmission output flanges from the same time period 911 sportomatic.

They are not as hard to find as you think. I put some feelers out on the bird board (Pelican Parts) and Rennlist and had a set in about a week for $30.00.

The early 911/915 sportomatic flanges have the same spline pattern as the 901 trannys (course splined). And there is one other difference... the dish (curved) part of the flange (the part that mounts to the axle is a tad deeper than the regular output flange. This allows you to...

Use the 901 tranny
Use early 911 ('72 to '73) Axles
Keep all the geometry in check so you don't need spacers.

And yes, supposedly they are stronger.

My race shop uses them on all of their racing 914s....

Hope this helps.

[Gary]

Qarl,

Cool tip on the sportomatic tranny flanges. Any idea what year range works?

[Qarl]

early 70's (71-74???)

later ones are fine splined