15 In Vacuum on Intake??

Have a 75 360 CID, mild cam:

Lift Intake: 465
Lift Exhaust: 440

Duration Intake: 224
Duration Exhaust: 214

Performer Intake, Holley 750 Mech, Headers, 9.5:1 Compression

I changed out the intake a while back, but just now checked the vacuum and it is at 15.1-.2

I used an adapter, and a 3/8ths to 1/8th inch vacuum port fitting to go into the factory drilled and tapped port on the passenger side in the rear of the intake. I'm getting identical reading at the vac port under the carb in front.

Is this okay? Seems kinda low. Just timed it. It runs good, smooth and doesn't ping, just seems like a low vac to me.

Also, the air/fuel needles are only like 1 turn out from all the way in... That doesn't seem right either. Does it seem like I have a vacuum leak? I just changed out the rubberized cork grommet type deals that seal the air/fuel needles. I will try to re-torque the intake today... A lot of the bolts like 4 of the water pump bolts, the alt pivot bolt, the thermostat, and some of the hose clamps have backed off a bit, not like loose, but not fully tight. I re-tightened them all yesterday.

Thanks...