Without seeing it I can only give it a maybe for now. Swapping out an old Homie for a newer gas engine will be some work but if it's Zenoah based like a lot of the gas buggy engines it can be done but it's going to take a lot of hardware to do it which should be easily available. Warehouse Hobbies used a lot of hardware that was made in-house or farmed out which was exclusive to them but those parts can be easily substituted.
As another heads-up, the Gator wasn't made to be a speed demon as over 50 MPH the handling gets a little funny on them. In their time they could handle the 25-30 MPH or so speeds but the bottom may be a little wavy.