Gear Ratios For a SWB

[jaudette3]

I'm setting up my '67 SWB primarily for light track and road rally use. It has the original engine built to 2.7 and the original transmission built with four speeds. I'm not sure what the current ratios are, but I wasn't impressed with them at Portland International Raceway a couple of months ago -- and that's the main track I will be running the car on.

I'm going to change things and I have a couple of options:

(1) I have a 915 stock 5-speed out of a '72 (don't know if it was a T, E or S) that has only 4,000 miles on it. If I use this one I will probably also install a WEVO gated shifter, which I really like.

(2) I've found a 901 5-speed newly built by a great shop with a 904 main shaft, very short gears (A-F-J-O-S) and limited slip.

I'm leaning to #2 -- what do you think?

Regards,
John Audette

[preS]

(2) might be too short for a 2.7, especially when you take it out in the winter. Besides that can a 915 handle the torque of a 2.7 better (we rally in a 65 w/ a similar set up and switched from the 901 to the 915 for that reason).

I would opt for (1) and have the gears setup to your preferences.

Richard

[kenikh]

Too short for a 2.7; almost too short for a 2 liter. Great box though!

[tfiv]

The second option would be awfully short for a 2.7, but it's really cool for a small motor (thats what I have in my S). If your 915 has standard gears you'll be selling the 2.7 short, and you'll have to take a hammer to you tunnel. AFMSX are cheap gears for the 901 and would work well with the 2.7. Earl Green had those gears in front of his 2.7 and it rocked. He spent lots of time on the track with that car.

By the way, I doubt you have a 904 main shaft if F is indeed your second gear. F is fixed on the shaft and was standard in all of the early 911s and 912s.

[Eric911S]

Hello: The 901 will work fine with your 2.7. I raced one for many years and they work great. A nice gear setup using stock factory gears is a,ga,n,s,z if you still drive it on the street. I would also install a Quaife or GT diff if you drive it on the street as well. Hope this helps. Thanks Eric

[a911s]

Buy both. Put a ZF LSD in the one you like, but do not put in a Wevo (it is overkill for your purposes).

[Eade Hopkinson]

The second option would be awfully short for a 2.7, but it's really cool for a small motor (thats what I have in my S). If your 915 has standard gears you'll be selling the 2.7 short, and you'll have to take a hammer to you tunnel. AFMSX are cheap gears for the 901 and would work well with the 2.7. Earl Green had those gears in front of his 2.7 and it rocked. He spent lots of time on the track with that car.

By the way, I doubt you have a 904 main shaft if F is indeed your second gear. F is fixed on the shaft and was standard in all of the early 911s and 912s.

You are correct on the F second gear. I have a 904 main shaft in my 67S, and it is: A, E, I, O, U, VERY SHORT GEARS. F is a standard 2nd Gear on a normal trans. To have E as a 2nd gear, you then need the 904 shaft. My top speed with this set up and 15 inch tires is about 118MPH at 7,100 RPM. On many Rgruppe runs, I would have people with 2.7 motors ask me what I had in my car, and when I told them a stock 2.0 S, they could not believe I was keeping up with them. Once I told them that when they went by me at 120, I had not backed off, but instead I was done in 5th at 7,100RPM, when they were just going into 5th!! If you want the most bang for the buck, put short gears in your car, and you will have a big GRIN every time you drive it. By the way, I have a 70-71 trans, completely rebuilt with a 904 shaft, A, E, K, Q, V, I think, with limited slip, for sale if anyone is interested.

[Alex Webster]

does anyone have a link or sheet that shows the original gear sets that were in each of the different boxes?
EG : 901/2 had gears a ga m s x ... etc (it didn't by the way!)

I have three gearboxes here and need to find out what is in them, assuming they have not been changed from stock (highly likely!) Before i rush off and buy some gears for the new box I intend to build.

[JohnT]

Putting a 915 (or even a LWB 901) box in a SWBisn't a simple swap. The Lobro driveshafts are different between short and long wheelbase cars. One cannot make driveshafts with LWB outers and SWB inners and LWB outer end stuff doesn't like to fit in SWB bananas. I believe you will end up changing drive flanges and perhaps even the differential carrier to make things fit.

johnt

[jhora]

Alex..

Airport gears AA,F,J,O,S