Well, after doing a little more work on the Tec 12.5 i think i'll give it a try..mostly because of the cyl head flow is quite a bit more than the briggs that i've flowed, the briggs head just dont lent itself for a "tunnel" port wich really helps flow on the top. I installed a 1.6" intake valve and a 1.250 exhaust valve for the flow test and will be set up with 1.5 ratio rocker arms and the valve lift is at .465. One problem i see as a major issue for reliability at 6-7000rpm would be the oil pump..what a scrawny little thing! I am awaiting on the delivery of a motorcycle oil pump to install..i'm going to try to mount inside the engine since the counterweight is removed but, if not inside.. i'll mount it outside somwhere. I will be getting a forged piston and the Arc rod for the 10hp tecs. and i have a billet flywheel too. Anyway, does anyone have any other ideas on this oil pump issue? --thanks Ron.