I've been repairing Quadrajets since they came out in 1966. They're the best-engineered carburetor I know of, and if you get one that's calibrated for a 350, not something oddball like a Pontiac OHC six, or a 500 Cadillac or a 455 Buick, etc., GM has done all the homework for you.
I grew up around the best performance shop in Nashville, Tennessee, and even back in the 50's and 60's there were people who thought they were smarter than the factory engineers. I ate a lot of good meals, and lived in a nice house from the money Dad made sorting out their screwups. Here's a big word of thanks to all of you backyard tinkerers for providing me with a comfortable upbringing! I'm keeping up the tradition, straightening out my students' half-assed attempts at reprogramming the computers on their rice rockets!
Jerry