Originally Posted By A990
Hemis had overdriven waterpump pulleys from the factory.


Depends on the year; prior to '69 the Hemi pulley ratio was .95-1 (same as the non-A/C V8's) but in '69 they went to a 1.20-1 overdrive. The other engines went to a 1.40-1 overdrive in '69. So there are no factory Hemi pulleys that would provide a 40% overdrive.

And, before considering overdrive pulleys, you have to know the vane size in the W/P.

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