Check out the Power Adder Forum at
http://www.corral.net There is a thread there titled "Harmonic Balancer + Centrifugal" that may help.
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1988 LX Coupe, 6 pt roll bar, 408 Stroker w/ Sportsman block, TFS-R heads, GT-40 lower, sheet metal upper, Tremec TKO, Paxton Novi 2000, Paxton fuel system, EPEC, Front Coil-Overs, Tubular K-Member