Edelbrock Carburetors?
No, Buckwheat. That's not how it is. The boosters are even different between the 1405 and 1406. You cannot turn one into the other because the passageways in the carburetors themselves are different. The 1405 is a performance tune while the 1406 is the economy tune. Edelbrock even backs that up. There's a thread around here somewhere splainin all the differences. There's a good bit. Alot more than just rods and jet and sprAngs.
I would also have to say with all else being equal, the 1405 would have more power, since it is the richer carburetor.
Rusty - If by "boosters" you mean the accelerator pump, I agree they are different. The 1405 has a 0.028" pump nozzle diameter, while the 1406 has a 0.031" diameter. A bigger diameter on the 1406. Course that could be a typo because one would think the 1405 "performance" tuned carb would get a bigger squirt, but comes right out of the Edelbrock carb manual. Course there could be differences in the plunger of the pump that would squirt out more volume, but through a smaller orifice.
As for the rest of the "passageways" in the carburetors, unless I saw factual data, I would NOT believe they are different between the 1405 and 1406. The primaries of both the 1405 and 1406 are a quarter inch smaller (both the venturi and the bore) than the 750 CFM carb. Hence the CFM difference. I've searched for the thread you're referring to, but haven't been able to track it down.
The reason I don't believe them to be different is, it looks like a cast part to me (I didn't look at specifically to determine, just recalling what it looks like from memory). And quality casting tools are EXTREMELY expensive. So I doubt Edelbrock would double up on their tooling costs. Not saying you're wrong, but unless I saw evidence of the contrary, I believe the differences to be: accelerator pump, primary main jet sizes, metering rods, manual / electric choke.
Either way, if the passageways are better (more power) on the 1405, good for me. That's what I purchased. And on top of that, the AFR gauge removes all the wondering of what's going on carburetion wise. I think I have the carburetor set-up as optimized as it can be. Only hand sanding metering rods would allow me to go further than I am. I doubt I'm going to bother.
Tonight I'm going to go home, swap the AFR gauge to the other bank, and dial in the idle AFR to be as exact to the other side as possible. Then drive it and double check WOT AFR. After that, I move on to hurdle the next challenge.
7milesout
