I have the Mag version of the .70... This is one powerful engine... I broke mine in with the 12x6 and then went to the 13x6... I find the engine runs (idle) a whole lot better with crank vent hooked up as per factory... Mine is coweled in and I wanted to use the vent for afterrun oil so I tried unhooking it, capping the intake nipple and running the line out the bottom.. I had to hook it back up to get a dependable idle on it..