I didn't try a pull start engine, I mentioned on another forum that I was going to use one in my new X5 and I got my head chewed off.....and a couple of experienced guys said the pull start engine would not fit with the mounts...maybe a washer between the chassis and the mount on each screw so the pull start will clear the chassis? Not really sure, I always thought it would work....shouldn't be too big a deal, just make sure you get a engine with lots of RPM unless you run on a small track, the speed of those 1/8 buggies is unreal!!! Have fun.