930 to G50/50

Hi All,
I am in the process of replacing my Porsche 930 4 speed with the Porsche G50/50 5 speed. There have always been questions about dimensions and such about these two transaxles and this seemed like a good time to answer some of those questions. I have already shortened the input/main shaft and the Bell housing on the G50 and am preparing to make the swap soon. If anyone needs a measurement please ask and I'll get it for you while I have the tranny on the floor.

Terry Oxandale

Skinny Man
Thanks Steve. This would be a future enhancement. So...can you explain why you shortened the front of the box (shaft/bell-housing)? Did you originally use the short bell-housing 930? Any photos to go along with this would be nice as well. What, if any, is the difference in adapter plates?
Hi Terry,
I had to shorten the bell housing on the 930 as well because it wouldn't fit in the GT40 bodywork. I'll take some pictures as I get closer to pulling the 930, I have to modify the frame because the slave cylinder on the G50 is on the bottom once you flip it. The adapter is the same for the 930 and the G50/50, I'm not sure about the G50/00 series. I am looking forward to "better" shifting and closer gear ratios. I'll get some pictures up after Christmas.
Hi Steve. How much should I expect to pay to have a 930 bellhousing shortened? Any recommendations where to have it done? Thanks.


Tim Kay

Lifetime Supporter

You could eliminate the slave cylinder and use an internal hydraulic release bearing. I'm kinda curious what flywheel you're using and starter (engine mount or trans mount)?

Hi Jack,
You can have it done at California Motorsport in lake havasu Arizona or at G Box in Bolder Colorado. They will be about $600 + shipping. If you have a mill and a lathe you can do it yourself, I did both of mine.

It is not the slave cylinder but the bell housing mounting for the slave cylinder. It will be an easy modification. I'll post pictures when I get there. The 930 slave cylinder is on the top out of the way. The flywheel and adaptor is from Kennidy Engineering in California. I am using tranny mounts. The starter is a Porsche starter mounted to the bell housing.
I finally got a chance to work on the GT. I was able to finish the rear sub frame modifications as well as the right transaxle mount. Hope to finish the left mount and shifting mechanism this next week.


When I fitted the G50 I cast a center section with mounting ears and separate bellhousing so the box ran normal way up which allowed the driveshafts to run straight. No adapter plate needed, runs a stock flywheel, full sized clutch, stock starter and is all quite a lot shorter.

Center section mold

Bellhousing mold ripped off of a Pantera ZF

Beefy side cover in billet

Just an update, I have installed the transaxle with all the shifting mechanism and mounts. I'm waiting for the AN adapter for the slave cylinder, it will be here next week. The transaxle shifts through the gears very smoothly, I can't wait to drive it. Hopefully next weekend.


:thumbsup:I finished the 930 to G50 swap on Saturday, I have run it on the lift and shifted it through all the gears and everything works great. I can't believe how easy and crisp the shifting is! Now all I have to do is put the rear bodywork back on and take it out on the road, I just need some dry weather. I also can't wait to see the difference in the ratios between the 4 speed and 5 speed... should be more fun to drive.