Ok I'll turn the screws out and fiddle with it next time out. AGAIN lol
The screws only adjust idle mixture.
running on main jets is a function of jet orifice size at wot power valve will richen it more . Do you know what they put in it and how that compares to what was factory for the 302? not saying this is what happened with your carb but at times when carbs go to the bigger rebuilders they get mix and match of parts.
They plugs do look a touch lean but unless you are running at the speed u have the issue at then immediately cut it off and jank a plug, you are getting what it was last running at which is idle to the trailer…
these plugs are out of my gm 5.0, from a couple years ago but i havent change my tune , this summer on the AFR meter i was a .5-.75 afr rich . The black ring around base of plug threads gives it away.
what ever jets you have in i would go up a step or two. So if you had .61 s in there go up to 63 or 65. Run it for a bit.
was fighting what i thought was a lean spot when nailing it. With the afr meter i saw it go way lean 18:1 and leaner, for a bit then it would go way rich. By seat of pants i went richer on jetting. the linkage for the accelerator pump had some slop. I had to bend the linkage rod a tad longer to keep the slack out of it… that delay in going way lean when getting on plan lasted longer for engine to recover and get into a good afr ratio.