Thanks, I kinda thought so to. It seems to be a no no, even as a back up carb. Thats what I call serious purists!
I use a "Gunson Colortune" to adjust carburetors. It's a 'see-through' spark-plug that allows you to see the color of the flame while the engine is running. Really neat and very accurate. It's a British product, but Google the name and you'll find state-side distributors. It's kinda pricey at $50, but well worth it for tuning just about any carburetor-equipped engine. The first photo shows the color of normal, correct combustion (blue with just a touch of orange). The second photo shows a rich mixture, very yellow. By slowly turning the mixture screws you can see the color change from yellow, to blue, to bluish-white (too lean). You can even check accelerator pump operation, mid-range mixture, misfire... It's pretty neat. But in general, the correct carb for the engine will have the correct jets, accel pump, etc. Adjusting the idle mixture is all that you can (or need) to do on a stock motor.
Thats an amazing product I never heard of! Well, my engine isn't really stock, but cliff says I will get my Buick carb back on monday so I can only hope I will only have to run this one a few more days.
I am going to play around with the whole Chevy Q-jet on a Buick motor thing next week. I have a BOP core but it is so screwed up its not even rebuildable. I think the only non damaged part is the bowl... But the Chevy Q-jet seems to be in good working order, I will do a quick reseal and inspect everything and then pop it on to see how it works out. Is it possible to swap out the capped idle screws on an M4ME carb?