Edelbrock models 1405 versus 1406 carburetors
The 3 step rods sit higher than the 2 step rods & the jets are taller as well. There is a whole lot more rods & jets ava for 2-step then there is for 3 step ( I wont pay for what is wanted for the 3 step stuff!) where the 3 step rods start to go leaner is a good .025-.030 diff from the 2 step rods. Again my little charger 273 has never ran this good with the stock AFB as it does now with the "tuned correctly 500 eddy" The ONLY way to tune any carb is via wide band o2 gauge! Best tool for this since canned beer! Not high jacken thread but I have spet a lot of time tryen to "cure" the secondary bog that thease carbs are known for & won the battle!!!! & this is how I did it above. The only problem with filing rods is if you go to far there isn't a surplus of them just laying around to try again. (at least for me there isn't)