I put this type of valve in place of both drain holes in the block. Had to put a T fitting for the knock sensor. These are quick, 90 degree throw, and being stainless, don't rust.
Living in Tahoe, and having freezing temps even in summer (at night), this was a must. (I have to keep the boat outside). The manifold cross-over has a quick-release, so that takes care of the upper block.
I've had these on my M/C's since '98, without any issues.
Maybe when I get real lazy, I'll replace the valves with stainless solenoid valves to drain without opening the lid.
I usually spin the motor for half a second (after draining) to clear water from the impeller and line. (I know, its not "recommended", but better than having them damaged by a freeze.)
(Message edited by awf_axis on March 31, 2006)
(Message edited by awf_axis on March 31, 2006)