Nigel,
Thanks for the info. I believe that the 60 or 70 bit is a ratio of the side wall height to the tread width. This means that, a Jez has pointed out, that I would have a larger diameter and hence circumferance. I am not sure about the gearing as I believe the car (MK2) has an american auto box. It is certainly smoother than the MK1 and shifts between massive ranges. Depending on load, it will shift from 2nd to 3rd at 2000 rpm to 5000 rpm (please see my post on Autobox Noise). Have you (or anyone on here) got any idea if the filters are the same across all of the autoboxes as I have a new one for the MK1?
By the way the car used to belong to the Insurance Valuation Officer Pete Parmenter. If anyone has any info on mods made to this car I'd be grateful for the info.