I trust you are speaking about modifying a 2.5cc (.15) car engine for r/c combat use? Assuming the crankshaft is long enough, and there is a drive washer on it (or you are able to make one if there is not), it may very well work. I have not knowledge on how car engines are timed compared to airplane engines, so my prop reccomendations may be off, but I would suggest an Master Airscrew 8 X 3 "Combat" prop, or the likely more available MAS or APC 8 X 4 prop. You will want rpm in the 17K to 18.5K range. Hope this is a starting place for you....
GPB