My 340 getting 6 mpg

The carb is decent, except for the throttle plate... its cheese. The accelerator pump arm screws wobbly pos's and you watch the throttle raise then dip while turning the speed screw in. Trash. The idle changes speed after driving it, raises.. lowers. When yoy come back from a test drive it's gone from 850 to 1100... then you push close the throttle and it's back to normal. It took enough return springs to necessitate standing on the throttle to open it.. I said take those springs off and buy a new throttle plate for this shitter. The thing is nice.. except for that part.
It got dark... so that's why we stopped with the tuning, for now. Going to drive it a little now and check plugs, check milage etc .
it pulls much harder, acceleration is smooth...and it has balls up top now it's not starving for fuel.
I like newbombs guesstimate of timing because that about as high as you would want it while still maintaining an advance curve. 8 to 10 advance is nice. His is all in by 2800 fwiw.
I normally will spend most of an afternoon test n tune with jetting and playing with pump shot.. but I got there a little later in the afternoon. It'll probably pick up 5 mpg immediately but expect it to get closer to 15 mpg. The higher initial means less fuel/pedal to get moving aka more power, less stink being cleaned up idle... not feeding from the mains... lowered throttle position. The timing shows a nice right before the bend initial and total burn mark.
It initially surged with the 65 jets, so immediately I went to 68's. Going to jet up depending on the plugs and feel... then he has a wide band he wants to get working..so that can aid his final jetting