Well it certainly wasn't the best way to build one I'm sure, but I took a pieca of 4x4 that I had & cut a piece about 1 1/2 ft long. I then screwed an adjustable motor mount to the end of it. I bolted an old fuel tank from an rc car on top of the 4x4. Car tanks work good for test/run in stands because they have 4 screw holes to bolt them on with usually & they have a flip open lid making it very easy to put fuel into them. They also have a fuel feed nipple at the bottom of the tank & a breather nipple at the top so you can run that to the nipple on your exhaust to pressurize the tank. Then I super taped a piece of goldenrod along the side of it to run a piece of push-rod stock through. Make the appropreiate bends in the end of the push-rod stock to accomadate the throttle control arm on the engine you are running in, slap the whole thing into the vise & your ready to run. (don't forget to open the gargage door) If you don't have a vise to put something like that in, or clamps big enough to hold it for you then you maight wanna use alonger piece of 4x4. My first one was about 4 ft long & I super taped it to the top of a 3 ft step ladder, crude version but it worked. I have since bought a vise & shortened it into the 1 1/2 ft version. Nothing fancy or trick looking, just a good functional engine run-in set up. I know alot of guys that don't even bother. They just run em in on the plane itself, or break em in during their first few flights. I like to run an engine in on the bench first, old habits of my Dad's I guess. Anyway there's an easy simple way to do one, maybe it will give you some ideas to start with until you figure out how nice of one you wanna set up. I didn't bother with a servo at the back for the throttle arm because I have different size & types of engines. This way I can slide the pushrod stock out & change the bends for the throttle arms as needed I just leave it long with the other end coming out the back of the goldenrod about a ft or so, & I can just operate it by hand. Works good.