Bill Kohnke

Mrs Murphy's transmission (a 901) died recently after a couple of harsh on track incidents, it had the brass spedo gear pushed out through the case.

I just recently had to scrap out a 74 due to way too much rust and the trans had the look of a freshly rebuilt unit. all new fasteners and all so I popped that one in.

I took her to the track at Calabogie, Canada and we had a ball. 4th and 5th gear everywhere.
The next week I did a DE at Watkins Glen. (I have a 3.0L in her.)
All sorts of power but a top speed of about 90 in 4th. and about 111 in fifth at 6200RPM Shift lights on and I don't want to rebuild the motor so there I coast alll the way from the esses to the Inner Loop. 225/50 front and 245/55 Rear Hoosiers.

Anybody have a guess what might be in the thing for gearing.

Bill Kohnke

Matt Romanowski

You numbers work out to a Q - V fourth and fifth. That is a weird combo. If the speeds were a little higher, you could have a S and X which is more common, but the speeds would probably be about 10 mph higher.

racing916

I agree with Matt, to have a X you are looking at 120mph. Bill, put the Q in third, the V in fourth and get a Z for fifth. With your motor you will be well over 130 on the back stretch.

GTgears

A real common old racer's build was AFKa (stock ZD flipped and put in 3rd)QV. There's a lot of gearboxes out there that have been regeared like this on a budget. The Q comes out of 4 spd 901 gearboxes.

GTgears

Only 4&5 are swappable in the 901/911/914 family of gearboxes. A Q 4th won't go into 3rd. But actual Q3 gears are not too hard to find either.