Couple of things.
Kyle, over time, I would completely unscrew those valves and let some of the rust particles out, particularly if they aren't flowing like they were on they day you first installed them. I don't trust petcocks either and have personally seen them get clogged. The reduction to barb would cause my CCOCD to stand up like hackles.
Milk has a point about the pockets, but Kyle's ice tray example has merit. When I winterize, even now that I am draining and pouring in antifreeze (I dry blocked before), I always pulled the boat around on the trailer and hit a few hills on the way. I had inexplicably put the bilge plug in once after draining and you'd be surprised how much water was left in there after a short drive. The water may have room to expand, but I'm not comfortable enough with the nooks and crannies in my block to make that bet. If you're stored inside, the odds of a hard freeze in Texas for your boat isn't enormous. Maybe just raise the trailer jack up to its highest point, then work it down to its lowest point to see if you can encourage any flow of whatever might be left in there.
Cranking the engine with the lanyard pulled will definitely kick the water out of the pump housing on an Indmar engine and is recommended. Those pump housing walls aren't as thick as the blocks. Not sure how much it does for the other nooks and crannies.
Last thing to remember is that the boats stored over water somehow (I forget how) stay a bit warmer than boats stored outdoors over dry land. Thermal mass of the lake or something. Makes sense.
Last, last thing is the old saying that is probably true that most frozen boat blocks happen in the south because people are always trying to avoid winterizing.
My preference is to winterize, declare an off season, and brew beer. Nearly 10 years of boat ownership and counting without a frozen block.
Previous: 1993 Prostar 205
Red 1998 Ski Nautique, PCM GT40, 310 hp, , Acme 4 blade, Perfect Pass SG/Zbox.
Be kind. Have fun.
Last edited by east tx skier; 12-12-2012 at 11:44 PM.