Well Personally from someone who has been used to driving RB C6's, Werks B7 Pro-C's, B3 Pro-C's, and Mugen Ninja JX-21's for the last 2-3 years, But I also had most of the SH based motors also in MT's--- SW .26, Mach .26, Mach 427 gold and teal,Lrp Spec 3, Mach .28 XTM 457 etc.... I would rate this motor as a B+, great price, great raliablity, decent power for small/mid sized tracks, Ok fuel mileage---Typical for the SH based stuff. It went a tad over 7 minutes on my first fuel stop in my main, I couldn't finish a 7 min qual up until then (out of fuel 6:30-6:45). It was getting better all night long though, Ran 280 after 1st qual w/2060, slapped 2050 on it and retuned for 2nd qual but didnt like it 270 ish, lot snappier but no top end(expected), 3rd qual put 2060 back on and a OD99 plug(stock plug was still good), ran it in parking lot and retuned it for 270, Ran 3rd qual flamed at 6:45 and came off at 255. Had to run a 10 min B-main and easily bumped, pitted at 5 min, motor starting to loosen and fatten up, came off at 225 but kinda doggy. lean it 3-4 hrs on top for A-main. Ran 20 min on 2 stops, motor doing very well but like I said it doesnt have the ball busting power of the race motors, Car is very easy to drive though, very consistant, It came off after 20 min at 235, Its gonna have to run at 250-260 after break in to run real good though, Im not a temp gun kinda guy except for the first day or two on a new motor, It probably wont ever see a temp gun again except for after the first qual next weekend.......... temps have settled down and its good to go, no flames from burnt plugs, crappy carb etc did evertyhing its supposed to do.. I may try a 053, I dont like JP-3's. anything I have ever use them on it destroys the top end. 053 much better imho. Great cheap club racer unless your trying to keep up with the really fast guys. If you do it will have to be from consistancy versus balls of the race motors. Oh and all of this was with the SMALL 7.5 MM restrictor and extra head shim....... I wanted to know how it was gonna do on fuel so I put that in b-4 firing it. 8 or 8.5 will get more power but you will sacrifice mileage......... Just depends on what you want/need...........Sure beats $300 every couple months............ If you want FAST your gonna have to spend some more $$$$$ LOL If you want OK FAST and very consistant driving this is for you and me LOL.......