Finally got all the appropriate bits installed in my T5 and as its a V8 main box I replaced the original main shaft with a s10 main shaft in order to align the drive gear with the driven gear . Although I've only managed about 200 mile so far all seems to be well . It matches my GPS. speed fairly well until about 55 MPH. then the needle gets wonkey . It flutters around a fair bit until I get to a speed I can maintain then it calms down a bit .

I suspect the speedo is getting into unfamiliar territory as with the original gearing it probably never topped 55 Mph.

The cable is new so I suspect the issue is in the speedo and I don't know of any way to correct this .
For the time being I guess I'll just wait and see .

John


good planning is no substitute for dumb luck