Old lawn chief fast off road mower with hydro

Thinking of making a new off road er that’s as fast as my other rig. This tractor is an old lawn chief with a 15.5hp Vangaurd engine with a tuff torque trans. If I pulley swap the front pulley will it make this tractor faster? Or does that only work with geared transaxles

Generally speaking, it only works with geared transaxles. You may pick up a little speed but nothing like a gear driven unit, and you’ll likely burn the pump up pretty quickly

I have a spicer 5 speed I can put in it but the pulley won’t come off it even after beating it with a hammer, I’ll try using that tuff torque as an experiment

I’ve found that if you cut the pulley off and just leave the hub, take the angle grinder and cut a slot down it along the keyway, then pound a chisel or thick screwdriver in the slot they open up and slide right out