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MG MGB GT V8 Factory Originals Technical - Diffs - Again? Sorry

I purchased a factory V8 some months ago. In general Iím very happy with it. I particularly like the torque. There is no comparison with my recently departed MGA. The one thing that does bug me about the car is the diff. It seems to be too highly geared and bangs and clunks on the overrun, particularly at our ridiculous local speed limits of 50 kph. Iíve done some research in the archives and in the V8 Register but have been overwhelmed with details. Iím looking for a strong lower ratio diff that will either bolt in or fit with minimal modification. Is there such a thing? Iíve seen several references to 3.08 Ford diffs. Are they a good thing? Needless to say I would appreciate any collective wisdom from the group.

Many thanks

74 GTV8
Tony Todd

If its a factory V8, it should already ahve a 3.07 diff. You can have a standard MGB rear end fitted with 3.07 gears or have others narrowed to fit the MGB wheel track. D&D in the states sells a GM S10 rear end with your choice of gears already set up to fit the MGB.

Suggest you check your gearing before doing anything else, just possible a previous owner swapped the axle or diff for a standard B unit, V8 crown wheel and pinions were hard to get hold of a while ago.
If you have the correct ratio ie.3.07/1 you should be showing approx 1300 RPM in direct top at 50KPH if my conversion is correct assuming also that you have 185/70 x 14 tyres. If RPM is higher then you may well have a lower ratio diff,standard MGB is 3.9/1 which would put the revs up to approx 1700RPM at 50KPH

If it does show 1300 RPM then you can start checking for the clonking problem, it could be just worn Universal joints which is an easy fix,if not then you will probably need some work on the diff itself. I believe there are anti clonk kits available with shims to take out excessive play. Also worth checking before doing to much work is that the u bolts locating the axle are done up tight. With the torque of the V8 the old axle comes in for quite a bashing unless you fit some form of anti tramp device.
Good luck,

K.R Jackson

This is a question for Aussie members - Does anyone know of a company in OZ, preferably in Sydney, who would be able to modify an MG diff housing to suit a Ford/Commodore diff centre. Many thanks. Tony
Tony Todd

If you can find an MGC being parted out, most came with either 3.3's or 3.07's, and the installation requires a minimum of fuss, you can even bolt on the B brakes, if desired. Also, if you use a wire wheel C axle, it is narrower than the disc wheel axles and allows a wider wheel and tire to fit under the rear fenders.

Best of luck.


Tony, check the Sydney "yellow pages" & also Aussie Street Machine mag. A few advertise there. Email me if you want to know who did my diff. I can't remember all the details off hand except he's located at Kogarah. Barrie E
Barrie Egerton

This thread was discussed between 10/03/2005 and 17/03/2005

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