396/375 hp/motor issues

[christopher teed]

hey guys,i have a 396/375 nova ss...i run a class that runs bias tires through stock manifold.recently had the motor rebuilt from a well known guy a year ago,it was dyno tuned ,i recently placed it in the car...been messing with it for a week after i got it running.it has a pulsating miss at idle and clears up somewhat at 2000 rpm but never goes away fully..has intial timing of 28 degrees,total of 38...it has a flat tappet bullet cam ,to factory specs...run through the valve lash ,ok..turned over the motor with starter switch and watched to see if all the valve springs seem to be moving up and down all the way,looking for lobe wipeout,seems ok..one thing it has basically has no vacuum until 2000 rpm...and then it has 15 on the vacuum gauge..also it goes hand in hand,when i put my hand over the carb the idl picks up showing a lean condition.wil be looking for vacuum leaks today...but starting to lean towards cam lobe issues ,by the way it runs,,,any help appreciated