Vacuum on 1968 GTS 340 4 spd.

Anyone have a stock 1968 Dart 340 4 spd ? I was wondering what your vacuum reading is. I bored mine 20 over with eddy heads KB pistons same cam . My vacuum is only 13 at idle. Engine Acts like it has a vacuum leak but cant find any. This includes putting a vacuum gauge on the dip stick tube after sealing valve covers and vacuum ports.I cant remember but I thought it should be around 16 In.
Thanks

At idle in gear?

Which cam do you have?
The early cam?