I have a 5 hp briggs racing engine designed for alcohol that will turn out 9000 rpms and make about 18 hp that would make your car fly. It's for sale for $800.00.
Or you can send me your engine and tell me what you want it to do and I can do the changes to make it run like a scalded dog even on gas. I'll charge you a fair price parts will be extra depending on what you want like billet high performance rod, racing piston, lifters, hot cam, carb mods,etc.
Norman