helo

a friend of mine has a r107 450slc. It has a 3spd auto box. Does anyone know of a 5 speed manual gearbox that will work with this car? Feel free 2 suggest non MB gearboxes

Rare as hen's teeth. It would be a custom job. An R154 is a good place to start. Compact, pretty strong, relatively common.

AMG offered a 5spd manual gearbox conversion for the 107, custom bellhousing and Getrag 265.

http://www.peachparts.com/shopforum/vintage-mercedes/268627-spotted-82-amg-500sl-w-5-speed-today.html

great suggestions guys

i think the r154 would be much cheaper than the getrag.

it has a 0.7 overdrive that would be great on the highways.

i thought it might need a custom bell housing.

Mercedes did a 5 speed for the 350 SL/C that would be a straight fit on the 450. But they are so rare that some believe they never existed (they did). The 4 speed manual found on the 350 would be a straight fit and is not as rare. If you really want a 5 speed then you do like I did: you find a 5 speed for the 6 cylinders, and you retrofit the input shaft, constant gear, front cover and bellhousing of the 3.5 four speed. There are also some reinforcement needed to deal with the increased torque (stronger bearings and additional key and key-way for the pinion of 5th).

The AMG set-up developed by AMG was for later 5.0 and 5.6 engines and the bolt pattern on the block is different. The AMG bellhousing would need to be modified and is rarer than any of the other parts I mentioned before.