[GordonGeesey]

I'm running a mostly stock 455 with 4X heads in my '69 GTO. Intake is a stock '69 casting, and I'm running an HEI distributor. The carb is a Quadrajet that decodes as coming from a '73 Buick 455. The car ran horribly when I got it - hard to start, poor idle, poor drivability.

I had the carb professionally built by a local guy with a lot of experience. He said the carb was a mess with mis-matched components, leaks, and missing parts. He gave it a very thorough rebuild.

Now the car starts, idles, and cruises a lot better. But if I slam open the throttle at any speed, it bogs horribly for a second or two before it accelerates. My carb guys says that the accelerator pump is set to deliver the biggest squirt, and that the bog is a "lean" condition. He reasons that the 73 carb is probably set to run lean because of the emissions in place at that time. He says not to mess with the metering rods, but to go straight to the main jets and open them up to richen it across the board.

I am not doubting his expertise, but will fattening up the carb help to eliminate this horrible bog at WOT?

If it matters for this conversation, the engine tune seems spot on as far as timing, etc. The car starts easy, and runs fine on pump premium fuel.

TIA for your input and advice!