Noticeable miss at mid-throttle

[BiltByMe]

I'm running a 350 with a MSD StreetFire distributor, Weiand dual plane intake and Holley 650 double pump carb. At idle the truck runs alright but there is a very slightmiss that you can hear if listening closely. I cant blip the throttle without it bogging hard and I don't believe its a problem with my advance. Im thinking a vacuum leak at the intake since i never retorqued the bolts after my break in period of the engine. The miss is very noticeable about 2500 rpm and there is a slight lurch that I can feel while driving. I've also seen fuel stains on the outside of the intake that would indicate a leak in the top of intake manifold but I've got the carb mounting nuts well torqued on top of a new gasket so I don't know why there would be fuel there.