Does anyone know of all the R&P options available for 901/911/914 transaxles? I can't find that info in my library. Most are 7/31, and I once had a 6/29. I'd like to try and find one taller than 7/31... like an 8/something, which I know went in the 915 box. Any ideas? Dr Evil probably knows!

7/27 was apparently an option. In sportomatics?
Ok, I see this topic is already discussed. Sporto pinion shafts won't work. Altering gears seems the best route.

or tire/wheel diameter

8:31 915/44 came out in 1975. Prior to that the 915 were 7:31 same as the 914.
915 gear boxes and gears are expensive. To convert a 915 for use in a 914, can run up to $10k
https://patrickmotorsports.com/products/tra...f01ea&_ss=r

If your building a water cooled 914, than the Boxster S or Subi trans are better options.

The only other 914/901 final drive I'm aware of is the 6:29. I have one in the race car.

Alternate gears is your bogey:

http://www.914world.com/specs/regearing_901.php

https://blueskymotorsports.com/index.php?op...17&Itemid=6

Although...~3000 RPM at ~70 mph is pretty damned optimal...

Issue is the fixed 2nd gear. You need a 904 shaft to adjust all gears.

I have a late Sporto 7:27 ring and pinion that I want to investigate. Yes the shaft is too long but maybe it can still work if shortened. The splines for the 1st gear might not be long enough though.

Here is a picture side by side, left 914, right late Sporto.

Click to view attachment

Depends on what you're looking for, right? For example, if all you want to do is spread out 3-4-5 then it's not needed.

My 901 shaft was modified by a 914World guy so it can accept 901 gears (not mentioning the name in case he doesn't want to do another one). Basically, the gear was machined off and the splines cut in by hand. Works like the charm it is.

But yeah, a 904 shaft is the best ticket, if you can find one at any useful price. Last time I went looking they were ~$1500-2000 used.

I ran a 6/29 in an early 67 911 for years on 205/55 tires. Fun around town but buzzing around at 75 MPH at 4K RPM got a little tiring on the highway!

I was looking for a taller R&P for my 3.0 using an already nice shape 914 box. Given the cost of trying to retain 5 usable gears in a 901/914 box, a Hewland 5 speed sequential crash box might be kinda cool. There was also a French company that makes a nice sequential 5 speed that would handle the 3.0 torque, but I forget the name. Last I looked it was around $8K new.

Sadev:
https://www.sadev-tm.com/en/products/2-wd-p...-transaxle.html

Or Hewland JFR200:
https://www.hewland.com/wpcproduct/jfr-200/

There’s a reproduction out there.

http://www.gboxweb.com/904ms.html

https://retro-sport.com/porsche-904-901-inp...haft-new-albins

https://www.thesamba.com/vw/classifieds/det....php?id=2169030

https://www.ebay.com/itm/184718509823?hash=...H8AAOSwpvJgVP2~

They are out there...