Your 98 probably had 3.92s. They had 4.10, 3.92, and 3.55's available. Chevy ran (runs?) 3.73s and I think it would be a better option behind the 318 and 360 than the 3.92s.
The 01 318 half-ton I had was twice the truck our 98 360-powered 3/4-ton was, and it didn't tear up the transmission, either.