Ok well my new engine is "hopefully" leak free now and I set the timing and TPS today. It still idles pretty rough, but better than before I adjusted the TPS. Before it would die when I gave it gas up to like 2 or 2.5 grand and then let off. Now it will come back down to about 600-750 RPM's and run really choppy.
I want to check my engine vac because I want to make sure there are no leaks from the intake. Unfortunately I had to grind part of the bottom of my Super Ram runners to get them to fit right and now I'm hoping I don't have any problems with the bottom bolts sealing them to the baseplate.
Where do I hook up the vac gauge and what would be a good reading while the car is running?

 

Paul,

Any connection to the plenum should be acceptable. The vacuum fittings for the FPR or HVAC controls are usually an easy place to connect a gauge. With a stock cam,you should expect to see something in the range of 18-19" Hg at warm idle. An aftermarket cam is likely going to lower those numbers due to increased overlap, unless you happened to install a "torque" cam for a truck engine set up for towing/pulling. With a 220/230° duration, I pull 17" on my LT1 at hot idle. That's actually a little higher than I expected, but I know that Comp really has the ramps pretty steep on the profile.

The key is that the vacuum is steady at whatever point you measure. As long as the gauge needle doesn't wander up and down a couple of inches (mixture problems), or bounce sharply (valve problems) you should be O.K. with any reading above 15.5" Hg.