Bought a '76 Chevy C-10 eleven years ago for $495. 350/350, 2WD, 3.73 rear (no limited slip), 15" tires. Lots of body rust, no air conditioning, runs great, pleasure to drive. Has optional heavy-duty rear springs (7 leaves), can cary 3,000 lbs. without rubber bump stops contacting axle. Recently using to haul gravel up steep gravel road. If too little weight in rear, tires spin and truck fails to go up hill. If too much weight in rear, truck stops on hill until some weight is removed. Would a bolt-in swap with a slightly higher ratio rear end with limited-slip be a good choice for better pulling power up a steep gravel hill? Anyone know of a part number likely to be found at reasonable cost in junk yards? Since the current rear seems to be in good shape, would it be better to put a limited slip in it? Any recommendations appreciated. Gas mileage not critical due to overall economics of vehicle.