Edelbrock models 1405 versus 1406 carburetors
Heres some more helpful info on ridding the motor of the classic secondary bog! (sorry spelling is gonna suck LOL!) I cured my 1405 on my 273 totally of the "bog" & now frys tires! I also installed an AEM wide band o2 gauge this my friends is the only way to dial in any carb on any car HANDS DOWN! noticed rite off the bat it was lean everywhere except idle 12-12.7 in gear. Once I got the cruise A/F around where it ran the best @ its leanest crusie for my little hi-po 273 it seems to be happy @ no leaner (leaner cruise metering rods same power step from 65x52 to 68x52 than 14.5-15.0 @ cruise. Then WOT was fat so a simple jet change (down to.083) got the WOT to 12.5! then that matha f#!*ing BOG......! on the o2 meter it would go off the scale lean when you would hammer it,i figured that but was shocked it went off the scale (gauge quits @ 19.9! then just shows 3 flat lines!) 1st thing I did was give it as much acc pump shot as possible... no dice still stupid lean when hammering it. Next I ground the lower edge of the secondary counter weight to give the air valve more attack angle (flatter at rest) helped ever so slightly,but still off chart lean when floored. So I had an old 800cfm eddy I got from kinda my brother in-law of sorts that he didn't want it anymore cuz he went fuel injection on his 455 buick. I opend it up to see the counter weights were heavyer on the top than mine & the acc pump has a mean spring on it compaired to my 1405,sort of like the marine carbs have. So I ground the weights on it to give flatter attack angle then it had & installed the acc pump to. at this point I also inlarged the acc pump discharge nossles to .035 holes ( I know eddy sells a kit with 3 different shooters but im cheap & have tiny drill bits!) Once back together that's when it started to make some diffreance! from off idle (not moven) it was gone!!!! but come back when cruisen @ apx. 40 mph & up RRRRRRRR!!!!!! & went off scale lean again. What ended up totally ridding the bog was I pulled the secondary clusters removed the early feed tubes in the secondarys ( the small tubes) peened the main air bleeds smaller to about 1/2 the stock size to give stronger signal to the boosters. I also noticed that the the eddy 800 secondary clusters had a brass plug in what would be the air blead for the secondary initial discharge port. I thought hum no air bleed would make it pull more fuel instead of air on the initial opening of the secondarys. So I plugged them off & put it back together & PRESTO!!!!! This little 273 has NEVER had that kind of throddle responce! EVER! I kept blaming the stock single plane for the low power off idle even with the stock carb! I shelfed the stock carb because I cannot find any 3 step rods the tune it & the eddy has the 3/4 inch acc pump well where as the stock afb has only 11/16 well (even less pump shot) I hope it helps you guys with your AFB/eddy carbs (completely change how the lil 273 runs!) a little time & man they can work real nice! but above all get a wide band o2 gauge! quit guessing! Feel free to ask qustions & ill get pics of mods if anyone wants them.