The 3 step is more precise BUT to dial it in like a factory set up carb is stupid hard. For ease of tuning & less math, use the flat covers from an AFB or the Edelbrock AFB so you can use the 2 step rods. The AVS rods are longer. That's why the rod covers have a dome.
Another good thing is the AVS has the boss mounts to drill and tap for the electric choke.
Edelbrock so SUPER STRONGLY SUGGETS that in NO WAY should you never use there parts on OE equipment. I have found it works just fine.
