i have heard this about mac's for a while. i run 3 cmb LS evo2's. essentially an exact copy of a mac (i have both). but my cmb's have NEVER been hard to tune or fuel hungry. 8 0z.'s will finish a heat in my jae .21. my tunnels & mono use 5 or 6 oz.'s a heat. so cmb musta done something to "refine" the design.
Never had problems with them being fuel hungry. My Mini Mutt sport 20 carries 8 oz of fuel and when I had the Mac .21 in it, it always came back with at least 2 oz left in the tank, sometimes more. My biggest issue with them is consistency, you have to walk a very fine line to get the maximum performance out of that motor. I still run the motor in .21 hydro, but if the boat takes any weird hops or the motor gets coolled with some roostertail spray, sometimes it's tough luck gettin the thing to come back on the pipe and it will usually conk out.
OH I see :huh: are you sure fit AA 21 into the MAC21 blue head or CMB 21 Valvola ? Can you show me picture compare 2 Sleeves ? thanls Allan
Justin, yeah I think the Toro will fit your needs really good! You will enjoy the torque and ease of use. Like we talked about, you will be using bigger props than you would be with the other motors. Some props you may want to try: 1452, 1650, etc. I bet Mark Sholund can give you more ideas. My best prop with this motor for heat racing is the V947 with added pitch and cup (your boat may not like the way it acts, so it would not be one of my first recommendations).
