Modifying A rover Vitesse axle for the Manta A Series.

One of my A series has a modified Rover sd1 V8 engine installed, however with the manta CWP ( crown wheel and pinion) ratio of 3.67, the acceleration is lethal but the car revs to hard for normal driving and fuel consumption is around 12 mpg.

I started looking for better CWP ratios, the only suitable one I could see listed was a 3.18 and after 2 months of looking I  soon found out these are like lens teeth to obtain, as they only came in the TE2800 and the Turbo version. I then started searching scrap yards and on the internet to find a suitable axle from another car which had the correct gearing for my requirements, and would be fairly easily modified.

I then came across the Rover Vitesse axle which is also made by Salsbury, the CWP housing was the same diameter as the Manta but budges in slightly different places, also the Half shaft tubes where the same diameter, Rover vitesses have 2 CWP ratios a 3.08 and a 2.84 which is perfect for the application. Also on later inspection the half shafts from the manta had the same splines as the rover, so no modifications needed there, which is a major plus.

The idea was conceived to remove the tubes from the manta axle and install them in the Rover Diff housing, this is the details of the process involved.

1. Remove the Manta axle from the car as per the Haynes manual, page 121 there is no point in listing it all here when all Manta owners have their bibles.
2. Remove the Half shafts as per page 122, A tip here if you do not have the special tool listed in the book for removing the half shafts, just pop an old rim onto the studs and tap round it, this will release the shafts.
3. Take the cover plate of the Diff housing and remove the 4 bolts that hold on the bearing caps then pull out the pinion gearing, this now leaves you ready to start the modification.
4. On each side of the Diff housing you will see a round circle which has been filled with weld to hold the Half shaft tubes in place, these need to be drilled out, center tap the hole and start with a 4mm bit and increase bit size as you go along until the hole is completely drilled out.
5. Tap out the Half shaft tubes from the diff housing, I found this a pretty easy task to do on the Manta axle they were not that tight, I had a fear that they had been installed by friction welding ( spun into the housing at high speed) but this was not the case. Hallelujah 
6. The next job is to strip the rover axle as in steps 2 and 3 above, this is easily done and the Rover Half shafts pop out very easy.
7. The Rover diff housing has 2 welds on each side of the casing 180 deg apart, I found these welds to be welded  proud so The bumps were ground off then center tapped and drilled out as the same as the Manta housing.
8. When the drilling process is complete if you find that the Half Shaft tubes are tight and do not want to release as I found on the rover axle. you can cut the tubes approx 15mm from the diff housing as they are not needed, then take an Air hacksaw and cut a slot in the remaining part of the tube which is inside the Diff housing. This will allow you to tap the remaining section out easily. 
9. At this point you have now got 2 good Manta Half shaft tubes and a good Rover diff housing, which you will find fit nicely together. The next step is to slot these together and temporally mount the axle back in the car, the purpose of this is to get the correct alignment to the drive shaft assembly. I will point out at this stage that the torque tube will have to be modified

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