Bought an engine to build up. My current car is a 92 Spi cooper. My plans for it were to change head and cam to Calver provided parts, however I then decided rather than have the car off the road too long, to buy a 2nd engine, get it ready then do a swap. Seems like a good idea to have a spare anyway! I ended up with a 1275 carb engine and box, however being a later engine it has the crank sensor hole as by that time the SPi was being fitted to the cooper variant, so should be fine for my SPi. This 'new' engine is a non cooper engine. I have always been of the belief that the difference between cooper and non cooper 1275's of this era is different head to up the compression / perhaps different valves (not sure) and different cam.
Is this correct? mainly, are the bottom ends the same ? I was thinking that as I am changing cam and head, it does not matter that the 'new' engine is not a cooper, but I have seen elsewhere something that suggests that maybe the cooper vs non cooper, has different pistons?
So basically the question is, what are the differences and if I fit uprated head and cam as advised by Calver, is there anything else I need to change on the 'new' engine, with regard to it being a non cooper engine? Is there something else that gives the difference in compression ratio for example (9.4:1 vs 10.1:1 if I recall, numbers may be a little out)