I have a mallory 2-14 PSI fuel regulator with a fuel return. I'm wondering what is a good way to test the regulator to make sure I get 4 PSI for my carb? I have a 0-300 PSI pressure gauge, but it really doesnt read that well under 90 PSI, it's for my tranny. Also, where do I hook up the vacuum adjustment to, it goes from the regulator to what? Thanks.

You need a cheap parts store fuel pressure gague kit (15 PSI) and some hose fittings. Hook it up in-line on the hose that goes from the regulator to the carb. Best of all would be hooking it up in-line right before it goes into the carb's inlet fitting so you KNOW the actual pressure the carb is seeing.

The main thing you need from the kit is the "block" that has inlet/outlet for the fuel line and also has a threaded fitting on the side that the compression fitting on the end of the gague/gague line screws into. Essentially the gague/guage line "T's" right into the side of it.

The vacuum fitting on the top of the regulator doesn't get attached to anything. It's there in case you are running a superchaged motor where the carb is actually under boost inside a "boost box". It allows fuel pressure to rise exactly with boost pressure so the carb doesn't lean out. For your application it will not be used. DON'T hook it up to a vacuum line fitting on the carb or intake.