Cutting the fins off to restrict cooling works just fine. Most car engines use a slide carb that require a different linkage to open it. Make sure you get a standard shaft, not an SG shaft. I run an OS 18 tz in a 24 inch crackerbox and have too much power to keep the boat on the water. I also have a Dynamite Mach .26 in a Dumas Hawk 3.5. Most car engines can be had in both pull start and non pull start versions. I like the pull start, it cuts down on field equiptment.