Rich bog off idle?

273 commando build with ld4b and holly 4150. Timing 12 initial and 36 all in. 904 with 3:73
8 1/4. 5.5 PV with 52 primary jets. My wideband is dropping to low 12's leaving stop. Comes on hard about 1500/2000 and adjusts to high 13's to mid 14's at cruise. Wondering how to lean it up off idle and keep the 1800 rpm up tuning.
I am no adjusting timing again, has to be all carb tuning. Gurus--------???????