There is no better upgrade than the EZGO Marathon High-Speed Motor-Controller Kit. We have several on the shelf that would be compatible with your Marathon since your eye gravitated right to the go-fast department. We can't blame you; we firmly believe the need for speed lives in us all. We were tired of seeing all these kits for the newer golf carts and no love for the vintage models. Thus the Marathon performance package was born. Now we can take that antique and make it a sleeper like no other. The first time you pull up on a brand new EZGO and blow his doors off, he's going to be trailing you till you decide to stop and tell him where you got the stuff to make your golf cart fly.With the high-Speed conversion kit, you will get a six-horsepower motor and a 500 amp controller. You will also get a weld cable set that comes in four-gauge and a heavy-duty solenoid. You may want to also consider upgrading your forward reverse switch with a heavier one as well. Give us a call here at Buggies Unlimited, and we will get you set up right.