Phil,
From the look of the photos in your build gallery, you need to spend some
time with a saw, removing all the excess bolt lengths (roll cage bolts and
steering wheel to boss bolts for instance).  Could save you a lot of weight
if done thoroughly, so the engine won't work so hard and get so hot. =8¬]
And, it's a cheap mod to do!
Nice to see someone converting and using an old Mini for real fun, instead
of just spending all their time on newsgroups (not this one!) telling
everyone how brilliant they are at Mini tuning. (Sorry, just a hobbyhorse of
mine). Best of luck.
Paul