915 transaxle question / info, a silly question... Options

[CCSmith58]

Hello 914world… Just renewed my Membership !! Now looking to get my moneys worth...

I’m having a ’75 914 built into a 914-6.
Maybe 10 or 20 years ago I might have tried to do (some of) it myself.
Now I’m more a “pay the money, turn the key” guy.
Here’s a “silly” question. Likely the first of many….
How does a 915 Transaxle work when converted to a mid engine application ??
Not looking for a “how to” just an overview for personal info.
I’ve searched for articles, webpages and / or videos and don't find much.
I find acknowledgements of the conversion but no detailed or even general description.
I see the term “flipped ring and pinion”.
Does the whole gear system run backwards ??
Does just the differential run backwards ??
How would a LSD work in a converted 915 ??
Are the available 916 Kits good ??
Etc...
Any info or links to info would be appreciated !!

[slivel]

The question of hp/torque limits on the 901 transmissions always comes up and I have commented on my experiences a few times, but here they are:

My car was strictly track only for 23 years and originally had a 3.0 l making about 275 hp and for the last 20 years had a twin plug 3.4 l making about 335 hp (290 to the wheels). I used a 901 gear box with the billet intermediate plate. I had two transmission failures over the years, one was the R&P and the other was broken tooth on 4th gear. During the last 15 or so years I had no failures at all but pulled the transmission every 3-4 years to freshen which included bearings, synchros and any other parts that looked questionable. I also drained and replaced the gear oil every season. I looked for gold-colored bits in the oil to get a sense of the condition of the bearing cages. I only used first gear with a light throttle and most race tracks involved gears 3-4-5 with a rare few needing 2nd gear on a tight, slow corner.

I think that you can save a huge amount of money going this route if you are sensible about first gear and do an occasional refresh. My race shop told me when I asked about a 915 conversion, that the money not spent on the conversion could buy a lot of 901 rebuilds. I fact, I built two race boxes, a long gear box and a short gear box. I always ran the long gear box and kept the short gear box as a spare. My long box has a Guard limited slip and the short box was built with a Torsen style differential.

Now that I have retired from racing and have converted the car to a street hotrod that just goes to shows or a little local canyon carving, I think the transmission may outlive me. Many years ago when I pulled my box during the winter off-season and sent it to be freshened, I got the freshened box back and re-installed it only to find that I had one forward gear and five reverse gears. My shop was very apologetic and instead of me pulling the box and replacing it had me trailer the car to the shop and they made it right. The tech obviously though he had a 911 box instead of a 914 and flipped the R&P.