Did you know the rod , piston and sleeve from a hyper 8 port will fit into a P5 , the one way out of most .28 engines are interchangeable. You can get a one way bearing out of the back of a pull start STS and use it as a one way in your MTX 4 Mugen 2 speed .. rear bearngs from a .25 nitro star will fit into a RB WS7 the rod from a .25 nitro star will fit into a CMB RS Pro . Front bearings on every .21 to .46 engine are completely interchangeable. The cooling head off a JP will fit onto an OS or Nova....Rear bearings out of an OS .21 and Nova .21 are identical ...

Fact is that the go tech like many .21's use a standard bench mark bore and stroke to comply with .21 regulations. or at least to comply with being under 3.5 cc . if you work with engines a lot , like i do you will notice that may parts are interchangeable. 90 % of all .21 engines share the exact same rod centres being 29.5 mm . its just a typical design. OS and CMB .21 have a 30mm rod centre . Just some interesting info for you .

Wether Go Tech is a copy or not is a moot point . I think in time people will be copying GO Tech because they are leading the field in quality and performance. Not to put down other engine brands because there are plenty of excellent engines out there. But i have to say Go Tech's popularity is not a fluke. Its because they are exceptional engines.

Hope this helps