When I got my '83 k10 the guy said they couldn't keep transmissions in it, they had just installed the 4th 700r4. It came with a recent receipt from a reputable trans shop to backup his story. The truck was weak as water, just wouldn't take off. It had a crate 350 with around 25k in good health. It was on a set of 33s. What could it be?? It had 2.73 gears in lol it man that ole gal was anemic!! 4:10 would have been my gear of choice if I would have just regeared it.