Once again, I refer you to my experience actually running the 500 on 4 different engines. You have not. Yes, the 350 would be a better fit, but you've obviously ignored what the OP posted, choosing to debate me instead. He's been offered a nearly new 4412 for $125. All he wanted to know was if it would work on a 360/390

 

Nobody advocated an 850 cfm on a 302. I did not imply that anybody did. There is no point to discussing this further as it was merely an example of "why smaller carbs work better on smaller engines."

You have made an assumption that I have not run the 500 on 4 or even more engines, with literally no possible facts or reasoning to back it up.

If the 350 is a better fit, then the 500 is not "PERFECT" as you mentioned before. The use of the word "perfect" was a point of contention in the thread previously. The 500 cfm may be a good fit, or even a great fit, but perfect is a whole different extreme.

If I had ignored what the OP posted, I would not have known to mention the fact that he has a good price opportunity on the 500 cfm, implying that this fact made the 500 cfm the obvious choice if it is actually in good/new shape.

Sometimes sharing other facts and information is just that -- sharing of facts and information. You made this statement:

"Makes no difference what it's rated at, it's going to flow what it's going to flow. As will any other carb he bolts onto it. The only time a carb is too big is when at WOT the pressure drop hits 0"hg and circuits stop functioning with the engine not turning enough rpms to have enough airflow through the venturis to supply enough fuel to prevent stalling."

This was misleading. I explained how sizing affects other things than this for the benefit of the OP, not for fodder for your debates.

 

I'm not sure if I subscribe to that theory. Who says rebuilding a carburetor is "pointless"? He didn't ask, that's true. So what?

Thing to keep in mind, the average guy doesn't want to make a career out of this stuff, but it's important to understand there's a whole lot more going on with carburetor calibration from the factory than most people think. They were tailored to the vehicle, engine size, weight, transmission, gearing, exhaust, altitude, with special booster clusters and jetting and power valves & the rest of it. They all look the same on the outside to the uninitiated.

Now it is true we might make the wrong assumptions about a poster based on their questions. If he knows enough about carburetors to declare the OEM carb unserviceable would he be asking advice on a carb? Well sure, maybe. For my part though I think it's just best to include the facts and most complete information available so he can make an informed decision.

USUALLY or maybe OFTEN, people would rather buy a brand new carburetor bolt it on and forget it, compared with (here there be Dragons) rebuilding a perfectly fine factory OEM carburetor, and while it will seemingly run "better" than it did, it will like as not run quite as well as the factory carb would with a good cleaning and the usual routine. Just an observation from watching this exact kind of thing for a long time. Maybe that isn't what's going on here, but it's usually a pretty safe bet.

 

OK, OP has enough info to make his choice.

If you have something new to offer, we will "discuss" it.

Thank you for your patience.