Have you disconnected your OSAC system?

Has anyone bypassed their OSAC system in your slant six engine?

Yes, but only do it if you want your car to stop running as if its shoelaces are tied together. Don't do it if you like hesitation and mushy acceleration, because you'll be disappointed with the results.

I'd assume you just connect the vacuum supply hose directly from the carb vacuum source, to the vacuum advance on the distributor.

Yep, do not pass go/do not collect $200.

Do you screw up your engine if you do this?

Not even a little bit.

How do you know if your OSAC system (mounted to the side of the air cleaner) is actually working?

It's a purely academic exercise. This system—OSAC stands for Orifice Spark Advance Control—was a cheap and nasty means of squeaking the cars past 1974 emissions standards so they'd be legal to offer for sale. The system delays vacuum to the distributor by a set number of seconds to reduce spark advance during acceleration, eventually letting vacuum through to allow spark advance during cruise. This lessens NOx emissions while severely degrading driveability (meanwhile, the EGR valve is in on both parts of that game, too).