I have one similar to Bart\'s on top of the mani where the pov use to be, except the 1\" plug I bought already had a threaded 1/4\" hole in the top so all I had to do was buy a 90 degree elbow with barb to screw into it.
Also, another place to to get a signal from is up along the fire wall there is a block where a vac line from the brake booster, and the big hose that leads from the intake mani from right behind the pov location. Both of theese lines hook onto this block. On that block on the firewall there is aother small nipple that isn\'t being used,and has a cap on it....atleast on mine anyways....this is where I get my bov signal from, and could be used for boost gauge signal.