I used a Davies Craig 10" radiator in my Mini (4EFTE). I specifically purchased the slimline version of the 10" fan which has the is 34mm at it's thickest part of the shroud and 50mm at the thickest part of the motor. I thought there may be an issue in that the fan uses flat blades not curved ones, but the guy at the radiator place assures me it should be fine for cooling. I'm unsure what size the mpi radiator is, but mine has a 300mm x 300mm core and the 10" fan fits perfectly. It only cost me $80 new.
http://www.daviescraig.com.au/Thermatic ... tails.aspx
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-Alan
I blame my dad for my love of minis. I think I was conceived in the back seat of one
I also blame my Dad for me being 6' 1" - not really the optimum height for driving a Mini.