I'd done a load of work to ensure that the big brakes would fit inside the wheels at the front, I hadn't particularly thought about the back, the calipers were well inside the mounting face & the radius looked OK. But all was not well & there was a clash on the "shoulder" of the wheel.
At the front, the wheel studs that were too short for the old wheels (only six turns of thread engagement) were worse with the new wheels (only three turns - eek!). But I have spare studs I thought - wrong. the short studs I knocked out were oversize ones, so the new studs fitted - to use engineering parlance - like a prick in a top hat.
I did some sums to establish how long the studs needed to be & how much I had to move the wheels to gain clearance, then ordered studs & 12mm spacers from Burtons. Only after that did I mock up how the back would look with the spacers on. Oh dear, Anyone of my generation will be familiar with "Carlos Fandango" & that's what the car looked like. I quickly called Burtons back & amended the order to 5mm spacers which looked acceptable, but left me with the problem of wheels that wouldn't actually rotate. There were three obvious solutions:-
1/ fit half worn pads so the caliper moved inboard - not very clever really.
2/ fit drum brakes - my brother has a spare set & I like drums on the back - they work, but that would require a whole load of faffing with the handbrake cables.
3/ "fettle" the calipers a little - I worked out where the touch was & fortunately it was only on some cooling fins on a very thick part of the caliper & they were hitting an angle, so reducing them down a little has bought me around 1mm clearance as I type, I'll do a little more work tomorrow & when the parts turn up from Burtons I'll be able to finish it all properly..