Basically, i have a 5hp engine in my go cart, and i was wondering if anyone knows if i can get a bigger engine for it and still have it work. Also whether or not someone if you can make it go faster, besides getting bigger tires, or what some people have suggested, using nitrous.

google go cart racing engines and learn how to run methanol, that ought to do it!

go to www.4cycle.com

We run 5 horse Briggs Animal on our race karts. We run a race carb and muffler with a race clutch. Depending on the class some run stock internals like gold plate and purple plate. The color plate I'm talking about is the restrictor plate under the carb. Stock appearing class is just that. The motor has to look like a stock 5hp briggs racing motor on the out side but you can do what ever you want internally. Even with gold and purple plates we have Karts that run around 50mph or so. The carb, muffler, and clutch have alot to do with the speed of our motors. There are some things that we do to our motors like run a very very thin race oil and some minor internal tweaks can be done (the gray areas in the rule book).