While Toyota's pricing on the device reflects an AMAZING amount of pride they hold for it it really is a simple and common device. Hit a local salvage yard and check under the hood of any pre-1990 Toyota (Celicas and Camrys should be quite easy to find and plunder) and grab a couple for a total of $5. They should all be the same size, but take yours to compare while you're there. When you get them home connect a small piece of hose and try to blow through... it shouldn't. Put it in some boiling water for a minute and try to blow through again... should blow through fine. Naturally take the tube off before heating the BVSV so you don't burn your lips.... can't believe I feel I need to add that disclaimer.
I wouldn't just open it to the intake outright and I definitely recommend against blocking it off. There are other ways of controlling it but they involve more effort than you really need to put into it.