Clearance - Harmonic Balancer, Internal Balance, 6.600 in. Diameter, Single Key Way, Cast Iron - 1972-86 AMC w/258 Inline 6P N: 17461. 01 Clearance (All Sales Are Final, Not Returnable) This replacement harmonic balancer is built to the original specifications and fits all 1972 86 AMCs and Jeeps with 258 Inline 6 engines. Balance Type: Internal Diameter: 6. 600" Key Way: Single Material: Cast Iron Hardware Included: No AMC, American Motors, Rambler Models Years 258 Inline 6 AMC 1972 1986 258 Inline 6 Jeep 1972 1986