What's the lower limit for doing this in terms of power. I'm thinking a mild 1776 can survive with the four factory dowels. I actually have an 8-dowelled crank (but no flywheel, unfortunately). Fit it, or stick it on eBay? I'm tending towards the latter...
H i would say put a HD gland nut and washer on the 4 pin crank, if you need the flywheel drilling for 8 dowelling let me know, but better to have them done together, ideally your better of with 8 dowel pins.