[tjthorson]

I think your limitation there may be the hydrostatic pump. If you try to overspin that thing, it will probably come apart.

We used to hotrod tractors all the time when I was in the biz.

Take a 10 to 30 tooth final drive off a mechanical tranny and put a 10 to 10. Instant 30 mph.

Unbolt the 8hp and bolt on a 20 hp.

Then we were making wheelie bars because every gearshift pulled the front wheels.

Total blast.

Hydrostatic? Stick to 5mph lawn mowing.

Find a rear engine mechanical tranny rider.

Oh, one more thing, if it has a 5 speed inline techumseh tranny, be careful. We warped 2 cases and spit gears out all over doing burnouts in the parkinglot at work. Never got em smoking, but some awesome squeals....