All OE ('68-mid '71) AVS's are lean due to the discombobulated gov't emission regs of the era that Ma & everyone else was striving to keep up with. How lean I ain't sure but I put an earlier AFB on a '68 440 GTX
(OE AVS) & it woke it up. AVS 3 step rods/long pri jets strip kits are as rare as hens' teeth but you can easily sub in Eddy shorter primary jets/2 step rods so you have some adjustability and a .001" change on a jet makes a far greater change than .001 on the rod. I would just get some jet/rod combos in there several tho or so richer than what is in there now. All that is needed is to make the domed metering rod caps flat. fill em with JB weld & cover em with scotch tape & invert em on your bench so the mud will settle flat then let it set up for several days. JB says 24 hrs & I like to give it more especially on a thick app of it. EDIT with more thought, the emissions off calibration of the AVS's is more than just the rod/jet AF ratio. Just me I might swap in the eddy items for a quick start or maybe even polish the rods down a few thousandths (say on the cruise and power sections & use the middle transition step to help you keep the (2) diameters seperate. People drill jets which from my exp with drill bits is highly likely way less accurate. I'd leave em be. some very fine sandpaper/solvent/smooth steady twirl & keep checking with your mike. You have a reasonably healthy build & I would look toward a much better carb, one of the modern ones that all of the systems are adjustable. #1 as Mr P body said get the LM2 meter plumbed in & see where you are at.