I have a gx160 that has a black mamba Sr cam, a RTC-8 head off of a predator and a NR racing .670 bored carb. It has a billet rod and billet steel flywheel, ZH8 flattop piston. The valves are 27 IN and 25 EX. She is a screamer and gets there quick. The head is not milled for higher compression, but that would be my last mod. It is ton of fun. Depends on how much money you can throw at it. You can put the cam into a hemi predator if you do go to a larger motor later on.