You need to cut the shaft for it to fit into the RC10gt, I first had the hobby shop cut it. But it was still too long, So I had to break out the dremel and finish the job, otherwise its pretty much a drop in fit. The Engine at first has been a little difficult to start, Due to the Stinger Pipe Flooding the engine. Im still in the process of breaking it in. At first I thought this engine was a dog, But as Ive been slowly leaning it out its showing some real promise, Right now this engine starts on the first 2 pulls. I figure a couple more tank fulls and Ill see what Ive got here.