Yes you must drive it. Do it on a nice day with the windows up and down. Drive at cruising speeds and also with it under some power if it sounded fine at the cruising speeds. Just to let you know these cars had problems with the u-joints if it was me I'd and the car was on a lift I'd pull the driveshaft out and see how freely they move and if you see any rust by them. They also had problems with the throw out bearing, noisy. So check when you're driving just put a small load on the clutch if the noise quits it's the t.o.b.