Was it a 3V with a torqshift, or the older 2V with a 4R100? Huge difference. The 4.30 axle helps too.
Mine was a 3v but only had a 4 speed. The 6 speed Tq shift prob makes a huge difference. Mine had 4.10's. Either way the 6.2 in my new truck pulls it way easier. The old truck was good when the ground was level but any more than a 2% incline and it was working waaaaay too hard.