Burris sells motor mounts and adaptor plates:-->
https://ssl11.chi.us.securedata.net/test.burrisracing.com/merchantmanager/index.php?cPath=4
for the GX390 bolt pattern, but I'm not sure what size bolt-pattern your engine needs.
You need to measure and post your GX270/8hp-clone motor mounting pattern. Take accurate measurements from the center points of each of the 4 mounting holes.
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To order a motor mount that fits your frame, you'll need to measure the distance between your 2 frame rails where the motor mount sits. Take these measurements from the center to center points of these 2 frame rails.
The International (Int) style motor mounts measure 3-5/8" from rail to rail.
The American (Am) mounts are for karts with 3" rail spacing.