From what I've been told, the #3226 GRRT R/C carb is too restrictive to produce full power from the GRRT. For maximum output, the #3219 Q500 R/C carb is just the ticket. You will either need to ask Morris Hobbies to remove a bit of the length of the bottom (its too long and rubs on the rotor), or you can do this yourself with a dremel or whatever. You also need to request the longer bolts to go with the carb (tell them you are putting it on a GRRT and they'll fix you up), as the bolts from the venturi are too short.

Mine turns an APC 7.2x8.6 racing prop at 22k on the ground and well over 24k in the air. I like it. I do wish they'd come up with a better way to hold the tuned pipe on. Otherwise its a great engine!

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