Whisky, Here's another suggestion. It looks like all but one of the engine set ups on the pictured airplanes have traditional motor mounts. It also looks like they are black "fiber filled nylon" engine mounts. If your rules will allow it, I would recommend he backplate type mounts, or aluminum beam motor mounts. The more rigid your engine is mounted, the more power it will make. The plastic mounts flex more then the aluminum mounts. We also have rear cover back plate mounts for all the engines, but I assume that your rules would disallow them, because they aren't straight "out of the box". I definitely am in agreement with Sparky on the bladder tanks. Tetra, and Jett are the most popular. They allow you to lean the engine closer to peak RPM, and then they don't lean out after 5 laps. Also, most of use a 4 oz. tank in our 424 Quickies.