I just had to put a catalytic converter on my 85 Toyota tercel wagon so it would pass missouri's happy little state inspection and now the engine surges when at idle, it did not have this problem before without the converter on it, is there anything I can do to remedy this problem besides taking the converter back off? I need it to pass inspection. I had to get a universal converter for it.

It's probably the back pressure tube coming up to the intake from the cat. Most likely leaning out the carb. Spray some carb clean around the base of the carb. See if it smooths out.
Did plenty of base gaskets and egr modulators back then, but it's been a loooong time.