I installed a petcock drain on both sides of my block to make winterization much easier. Its a very simple mod that makes draining the block easy, and once done you dont have to worry about cross threading the knock sensor plugs every year when re-installing. With this setup you can drain the block in about 3 minutes, which includes opening and closing the petcock valve.
I picked up the parts at a local Marine store, unfortunately I cant remember what size thread it is. Easy way to do this is to take off the knock sensor, remove the plug and take it with you to match up the threads. The picture should show you all the parts you need. Make sure and use teflon tape on all threads to prevent any leakage. It has worked great for the last couple years with no problems.
The picture I posted is the side I ran my hot water shower line off of, this denotes the red line coming off the cross connector. The only thing you MUST do is keep the knock sensor in-line with the block. DO NOT run it off the side of the T or cross or else your motor will start running poorly. If you do not have a knock sensor on your motor, disregard this. In this case with no knock sensor you would only need an elbow, rather than a "T" fitting.
Hope this helps, if you have any questions please ask!
*** After looking at the picture, it looks like 1/4" NPT, but to make sure bring the plug down with you. All of these fittings can be found at your local hardware store.
Last edited by fman; 10-19-2010 at 6:54 PM.