If you are still searcing for a 671, you might want to check ebay for a used unit. They sell fairly cheap there. (Although, I am a firm believer in "you get what you pay for")
check out Don Hamptons site - hamptonblowers.com
He knows his stuff, and sells the 671 kit cheaper than anyone I've seen so far. You can buy the blower itself, of the entire kit, which includes the snout, intake manifold, and everything else you'll need.
"I seem to be missing this small thing called traction. Hopefully I can find out where to get some."