[spuggy]

I see no mention of an LSD. IMHO, you'd really appreciate a 60/40 LSD set to about 80 ft/lbs in that car. Best money I've ever spent on either of my transmissions.

A Guard Transmission (GT) clutch LSD is probably the very best available, but pretty spendy in the UK with import duty/taxes.

The Gripper guys told me they've made G50 LSDs before (and will again if asked), they just don't list them on their web site.

However, with a Gripper, you need someone who knows how to tune one to set it up for you for your intended use, as well as to install it. Because those guys just make diffs.

Mike Bainbridge has worked with those (Gripper) diffs extensively.

Originally Posted by ALEX P

would really like to not have to cut into the torsion tube

You may still have to at least cut the cover away to get the extra half inch you need. My '77 did.

There's a one photo on this thread that'll give you an "oh, OK" moment: http://forums.pelicanparts.com/porsche-911-technical-forum/440191-verify-g50-shortened.html

The welded cover is just a welded cover. It's OK to cut some of that away.

Some cars don't need it; I've heard of earlier ('74) and later (SCs) with G50's that didn't need this, no-one seems to know quite why some do and some don't....

G50-00 Gearbox (Not sure if this is the only G50 Variant that fits but appears to be the shortest)

All the N/A, 2WD, 5 speeds are same length I believe, if fitted with the early (pre-964) nose cone. You can't convert the 964 4WD box to 2WD nicely, don't bother even though they're cheap as chips.

G50 Pedals and master cylinder (possible aftermarket – Tilton?)

87-89 pedal box. 964 one doesn't fit.

3 x Hydraulic lines

Shortening the bell housing moves the slave further away from the master - in the same way that the shift coupler also needs to be extended by the same amount/same reason.

Patrick Motorsports make an extended, full-length hose. Or a short extension hose (just source new stock hoses locally).

PMS also make a coupler extension. They can provide a full package of parts/fiddly bits.

G50 Shifter assembly

Replace internals of the factory shifter with the J West short shift while you're in there - and replace the factory coupler pillow with the J West one.

Fabulous stuff - you'll not regret that choice.

G50 front mount / adaptor to 915 chassis (Patrick Motorsport?)

This is an excellent piece - my tranny guy was quite taken with it. It also lets you use 915 engine/tranny mounts - including WEVO ones - instead of the bonded-in, non-replaceable ones.

Reservoir and line
Slave Cylinder

Yup.

G50 starter motor

When the 915 was built up for the 930, I bought a hi-torque starter motor (Edge) from Cambridge Motor Sports in 2006 - and just re-fitted that to the G50.

Clutch kit
Flywheel (Patrick Motorsport?)

Probably best to buy a package from PMS; there's some funkiness around the throwout bearing/flywheel bolts/release fork tube that they've got down pat.

Unless you really want to go DIY. Basically, you're just converting to a 76-77 spring-centered 930 clutch (factory friction plate good for around 500 ft/lbs, so you don't even need "trick" plates like Center Farce or whatever), but you do need to get the flywheel and bolts, TO bearing right.

And the work involved other than fitting the above is:

Shortening the bellhousing of the G50 by the 29mm or so – Are there any threads or info out there on the best way to do this?

Shortening the main shaft of the G50 by the same amount - Are there any threads or info out there on the best way to do this?

Give it to someone who's done it before. Preferably some who's done it many times.

Do you have to completely dismantle the G50 to remove the main shaft to shorten it?

Most certainly. I don't know if the weld-on 1st gear needs to come off, but I believe you should certainly re-harden the main shaft after machining.

I've seen people quote $1000 for the work which seems a lot for simply doing the machining work so presumably the rest is in the labout to strip and reassemble the 'box?

LOL. No, that figure doesn't include stripping the box. 600-1000 USD is pretty much the price for performing the machining on your parts. Or, in other words, parts not included.

BTW, even though 915 rebuilds have been edging up for years, G50 boxes are way more expensive to go through. A G50 with 120,000 may actually need a fair bit if the spec is "replace wear parts if questionable".

But then I expect to be stuffing over 500HP through mine.

Any advice on offer or anything that I have missed out there would be great as even if I don’t do it and live with/rebuild my crunchy 915 - It may be useful to others

If I were you, I'd talk to Mike Bainbridge of MB Engineering. I'm sure I discussed the machining for this with him years ago when he built up the 915 I used until the G50 became necessary - and he could do pretty much all of it.

PM me if you aren't clear how much all this costs, or need more details.

Frankly, with "only" a 3.6, I think I'd put the car on an aggressive diet, build up a couple of serious 915's with LSDs, internal oiling (spray bars) and stiff cover plates/bearing retainers etc, uprate the stub axles so you can use G50 axles. And still have multiple buckets of cash left over instead...

Unless you drive it seriously hard (like competitively), it probably just doesn't make sense for that power level.