its easier to fill when not in the car. a 7.5" axle takes 3.5 pints, (yes i know you have an 8.5) and a B body axle takes 4.25 pints. sorry, using a 78 olds manual for specs.
because you have an 8.5 and an aftermarket cover, i would put 3 quarts in it while its out and then drain out any excess once its in the car. jmo
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