Rat Rail part 2 Build and Finnish

Thanks for watching my Part #2 build and finish of our rat rail. This was a fun challenging project making a hydro-static go cart from a lot of laying around parts. ill up-lode another driving video sometime.
If anyone can help make our cart go faster we have tripled the engine pulley and it barley has increased the carts speed.... does a hydro-static lawn-more diff have a rpm limit or... if you know or can help ide appreciate it.