1045 steel these dampers are designed to be installed on race engines that may ... rpm optimum damping occurs in the 6500 to 7500 rpm range the machine work on ... these dampers is second to none and the critical fit tolerances ... counterweights this feature allows for swapping weights between dampers ford or adding ... them to internal balanced dampers chevy if you ... with either a different counterweight ford or an added counterweight chevy this ... 90006 6.4 damper for early small block ford 28.4 oz in ... 6.4 damper for `81 later 5.0l sb ford 50 oz in ... 168.97 90008 6.7 damper for 429-460 bb ford 173.97 90009 7.5 damper for ... 352/390/406/410/427/428 bb fe ford to 68 196.97 90010 ...