AFB or AVS for 67 formula s??

yes 68 model year was the first year of the severe emission regs of that era and the first year of the AVS & the main reason it was developed. As far as those OE carbs go the (earlier) AFB was a far better performance carb than the AVS plus they (AVS's) are all emission calibrated lean possibly including internal systems other than just main metering & things were discombobulated back then with Ma (& general merchandise and furd) trying to meet ever changing gov't regs. & OE AVS 3 step metering rod/tall jets strip kits (needed) are almost non existant these days but you can convert to an eddy strip kit with 2 step rods shorter pri jets & pick a kit with rod dia's jet dia's close to what your AVS has in there. Just me I 'd get one of the modern carbs that has all systems adjustable & get an LM2. For OE I'd get an AFB from a 67 440 & you might call "the carb shop" in Eldon missouri & speak with the owner & pickhis brain. mfr's high quality kits & even mfr's his own rods/jets so I think he knows what he is doing. I've spoken with him, nice guy, stuff is pricey but I'm sure is the best. EDIT fill the domed AVS metering rod caps with JBweld then cover em with scotch tape & turn em over so the mud will settle flat against the scotch tape & let em set up that way for several days cuz the eddy stuff requires flat caps (which the eddys have).