Precirotate pr21c .21 engine is a 3 port and is modified. Motor screams an you can get it for $174 on amain. I have one in my buggy and its more than enough motor for any thing. And great mileage. Or i can get a ascendancy g5 which replaced the grp motors that are great and are around $240. Or maybe try the werks b2 for around $160 and is a 3 port too.