Those heads will work fine if you open the runners up, raise the roof of the port as much as possible for the entire length of the runner, narrow the port divider to 1/8" and work in from there being careful not to cut into the headbolt hole, leave the port floor alone except for blending to short turn into the bowl, match your intake to the new roof height and divider width. Unshroud those valves out to the bore line not gasket line. Blend your lower cut below the seat into the bowl. They'll work fine and probably end up at a 170ish intake port volume. The set I did the chambers CC'd at exactly 64 after the deshrouding and a .030 mill. I did spend a ridiculous 30+ hours on the ports though
. If you do the port work make some go/no go guages out of heavy wire so you can check dimensions as you cut- this way the ports will be more equal when done.
The 750 VS carbs do seem to have a really rich idle circuit and with your cam the overlap isn't helping much. I bet if you open up the secondary throttle blades just a tad with the setscrew adjustment in the baseplate and readjust your air/fuel mixture screws the richness will drop quite a bit. If this problem is related to rpms below 2500rpms I'd say it's more than likely an idle circuit problem. Make sure your idle mixture is on before making jet changes. JMO's Bob