I know the alternator in mine is the stock one. Looking like I'll be stepping up to the Mean Green sometime in the future. My battery cables were also pretty corroded. I replaced them and it fires right up now.
Denis A. Baldwin
1991 YJ 99 Vortec 5.7L, SM465, NP205, 14 Bolt Rear, Dana 60 Front, 5.13 Gears, Detroit Lockers, 395/85R20 46" Michelin XML tires on 20" XD Wheels, Cherokee Offset Springs (10" front to back stretch total), Bilstein 5150s, 1in. BL, custom cage, Warn M8000, Double D Dash/OHC, 4Low Front Stinger Bumper, DirtWorx Rear Bumper WTC, Tube Fenders, Comp Cut, 1 Ton HD Kingpin High Steering and PAID FOR.