The dampers on 216-261 and some GMC's is different than the typical V-8 damper.It's like a sandwich,plates with rubber in between,it can't slip and spin due to the construction of thru rivits.
Fred,a third place,Dale's Damper rebuilding does a better job for less money,about 100 bucks for any damper,search the web for his address.Dale says he uses a rubber with the same hardness as the original to keep the damper tuning proper.The weight of the internia ring and the rubber is tuned for a certain rpm,whatever that may be.
I was gonna use a Fluidamper on my recent 302 GMC build,but I heard of crankshaft and bearing failures directly related to the use of this style damper when used on GMC 6's.The 302 damper ,at least most of them,is similar to a V-8 type,the outer ring on mine slipped and when I removed it,the outer ring actually fell off!!!
