AR, this works well as a vacuum restriction device. it's usually available at any pet store that sells fish tank stuff. i and others here have used these but it obv needs to be kept away from extreme heat.
here is a pic of the choke breaker A port from a carb that does not use the 'jet' restriction device. you can see it has only a pinhole opening compared to the regular port above it. i have not noticed a trend on which years use it but i believe this carb is from a canadian automatic so that might have something to do with it.
and lastly, i'm afraid i have no spare jet restriction device. i must have used it on the most recent project terc.
It is a very good idea to have the jet in place, or a very small orifice in the line, to the choke breaker as a backfire is very likely to destroy the diaphragm in the CB w/o some kind of protection. The CB assy's are getting hard to find and very pricy.
these valves, and similar bits used on the vacuum/induction/fuel system, were common to all models that used carburetors, and even some that have fuel injection, so I would think they should be available from the dealer if not aftermarket. if you can find a Toyota part number, or the exact name they are called in the factory service manual, it would be a lot easier to track down.
social, are you looking for a TVSV? that's what it almost sounds like. that's the little vacuum tree found at the front of the engine on the coolant outlet housing. here's a drawing of one from the factory service manual.
if that's what you're looking for, they are currently only available new from toyota for the steep price of about $100. some members have had success tracking down new ones from asia for cheaper but i checked that route recently and none were available. if you can find a low miles car with one at a wrecker, its TVSV might be good but i have personally never found a used one that passed all the TVSV tests in the FSM.