Those clusters are very easy to swap out...I have the same situation with a 73-450SL I bought last year. Mileage says 47,500, condition says "it ain't so"

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__________________
Gary


1973 450SL
1999 Silverado 4X4 Ext Cab
1999 Mercury Sable
1972 450SL Parts car

Previously owned keepers:
1967 MGCGT - 3L-6
1972 Mustang Fastback - 351C

Current Cylinder Index: 37