I'm installing a Victor 5.0 intake and it has no port for the heater hard lines. I'm not running heat anyway and need a way to block off the heater port on the water pump. It's the larger of the two outlets. This image of a pump is not the correct one.
[
They sell caps that you can hose clamp over the fitting, usually in the help section at your local parts store... Or if your looking for a more perm solutiion you can braze a copper cap over the fitting.
I've always wanted to try to pull the fitting out of the housing, then you could tap it and use a NPT plug.
If the port is pressed into the casting it can usually be removed by crushing it with a pair of vice grips and gently worked loose. You can then tap the hole (if you can control the shavings) and put in a pipe plug, or use a press-in plug (like a freeze plug) of the right diameter along with a reliable epoxy. Manley offers an excellent two-part epoxy for this kind of thing that bonds well to steel and aluminum.
The easier option is not as reliable. Auto parts store sell rubber bypass caps that simply cap off the port and fasten with a hose clamp. You have to keep your eye on them because the chance of leaks does exist.
Lastly, Edelbrock's water pump comes pretapped with threaded brass ports for this exact purpose. If you're removing it ot modify it, you could just upgrade it at the same time. Scroll down to part number 8840: Edelbrock.com - Water Pumps - High Performance