<VV> Early vs Late Fan

[Bob Gilbert]

Hi,
Other than the different hole in the middle and the retaining bolts on a
different radius are there any other differences between an early and a late
fan? I have a friend who could drill out the main hole for me plus drill new
holes in my early fan/pulley to make it fit my late bearing hub.
Before I say yes, is there any reason that I shouldn't do this?
Thanks,
Bob