I've heard the usual stories of belts breaking on Powerdynes, but I think a lot of them are for sale, (along with a slew of A-trims) because people are always upgrading. A Powerdyne is good for only about 10 psi.
Dustin runs mid 11's with his on a stock suspension.
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1988 Mustang GT
11.8 @ 123 (7/14/01)
1992 BadAzz Wrangler
1993 Explorer
See my car at:
www.mustangworks.com/cgi-bin/moi-display.cgi?179