Why does my buick 455 bog down in gear with a 650 cfm carb it ran fine with a leaky old 750 cfm carb?

Do you mean it's flooding out while idling or is it when you are driving? Is this a Holley carb? There could be several reasons. Fuel level set too high, a leaking power valve and so forth. I need to know a little more about what you have to really be able to help.

well its fine until i hit the gas to get moving then it doesnt want to see high rps but with it in park or neutral it will rev to 6500 easy as pie.

it was the cam that was replaced at some point right before i got the engine and it was off a bit, and the pluming for the vacume was bad, runs like a raped ape fix it a while back