if i pull the drain plug on only one side of the block BBC 502 will this drain the whole block? i cant for the life of me get between the 2 motors to get to the drain plug...i can only drain from the outside of the motors. I would say about 1 1/2 gallons of water came out.

No, that will get some but not all! Manifolds & risers need to be drained & flushed with RV antifreeze.

why for the life of me do i see these same questions year after year?you spend a small fortune on your boat,then want to winterize it yourself without any knowledge of how to do it correctly..then you ask people on the internet that you dont know how to do it.spend the small amount of money with a reputable shop to do it right,if they dont ,there insurance will take care of the problem..your insurance as a boat owner will NOT cover freeze damage jus tmy 2 cents....

ok i was just asking about the block drain....not how to winterize, not is this enough for winter. but just the simple question will this drain the blocks...i didnt know if the casting of the block had a water jacket that was shared....thanks for the info....

No, you will still have water in the side not drained, up to the level of the circulating pump openings.

The only shared passages are the intake and cir.water pump, with the pump being the lowest

and once the plug is removed you sometimes have to poke the inside of the hole to get the watrer to come out and make sure you get it all out..then gige the engine a quick start and shut it off,this will get the water out of the pump,,also need to pull the plug in the oil coolers and pull off the hoses if ytour not using antifreeze..

i drain blocks empty. then reinstall plugs and pull thermostat housings. and fill blocks with real-not rv-antifreeze to the level of thermo hsng flange. needless to say, drain exhausts empty and leave them that way. also, put your drives back down when boat is where itiis gonna stay for 4 to 6 months. shift cables, boots don't like to stay stretched. and every spring we get millions of posts-"my drive won't go back down! what do i do?"

I can't figure out why boat manufacturers don't think of this when building boats. Part of building a good boat ought to include remote drains and flush fittings. Also oil drain hoses should be standard equipment. A few cheap parts could increase owners enjoyment of their product. On my ski nautique, I take the time to install brass valves in all the drains(save the knock sensor.). I can turn the valves and drain the block in less than a minute.
In a tight twin you could put a brass nipple fitting in the block and run a rubber hose to a valve drain. Would be well worth a few minutes to do it.

Thanks for the input...downside with all your ideas, the only way to get to it is by pull the headers....im in no way going through all that hassel when i can just dump straight anti freeze in and the little water left will mix with it and be enough...
But back to my original question, I was just unsure if it would drain the whole block or not and you answered it so thanks guys!

I agree that it is frustrating this time of year, the winterization and upgrade questions....however, if they are going to learn they have to start somewhere right? We all did.

BTW, I know of two people that have winterized improperly, and were both covered by insurance. One was a 3 year old formula. Insurance does cover stupidity