Compared to the rest of the components in your race engine, freeze plugs are a nickel-and-dime part. But poor installation practices will allow coolant leaks and major headaches.
In your racecar, a cracked block from frozen coolants in the winter isn't usually the problem. Leaking freeze plugs that dump coolant on the track, however, is. If you have a freeze plug work its way loose either from the vibrations from an engine operating at extended high-rpm levels or from occasional overheating, the coolant dump is usually right in the path of your rear tires. And a spin-out or wreck from a faulty plug is the last thing you want.
Of course, it is rare for a freeze plug to pop all the way out and dump coolant all over the racetrack. The more common problem is a slow leak that aggravates you to death. It is hardly worth pulling the engine to replace one plug, but the result is a slow coolant leak that constantly makes your car nasty.
With that in mind, here are a few tips for installing leak-free freeze plugs.
Freeze plugs can normally be bought in packs sized specifically for your engine from most automotive stores. | 
You generally want to avoid the steel plugs (left) and instead use brass freeze plugs (right). Since most racers run pure water in their cooling systems, the steel plugs can corrode and may eventually weaken and leak. Brass plugs won't corrode, but you will have to be careful on installation because they are softer and can easily be deformed. I got these from my local speed shop that supports racers. | 
Most packs of freeze plugs for Chevrolet small-blocks will also include several press-in plugs for the front of the main oil galleries. These are used in stock builds but have no place in racing. Throw these out and replace them with 1/4-inch pipe plugs just like the ones used in the rear of the block. |
If you need to remove an old set of freeze plugs, the easiest method that also won't hurt the block is to use a punch and hammer. Place the punch on the lip of the freeze plug and knock that side of the plug in to spin it in the hole. If you try to place the punch inside the cup of the plug you will just knock a hole in it. Be careful not to scar the block. | 
Once you get the plug spun in the hole, you can use a pair of pliers to pry the plug from the block. | 
Remember the press-in plugs we showed you earlier? The three holes in the front of the block for the oil galleries are where they are intended. Instead of using them, tap the first portion of the galleries with a 1/4-18 npt pipe tap and plug the holes with a 1/2-18 pipe plug that you can get from most automotive or hardware stores. Make sure to use liquid thread seal to prevent leaks. |