My 72 Olds surges at idle in drive?

[sep455]

I recently rebuilt the engine on my 72 Olds with 455, 9.5 compression, 214/224 dur cam, and was using carb #7041250 which ran great. I then decided to use a more period correct stock #7042251 quadrajet, rebuilt it, idles fine in neutral but has heavy surge at idle in drive? I checked for vacuum leaks and found none. I also noticed some nozzle drip. Adjusting idle screws, no help. When I covered top of primaries with hand, idle smoothed out. Iv'e been getting mixed opinions to either enlarge the idle tubes or enlarge the idle air bypass holes in the slots at the bottom of the base plate? What do you think? Thanks, Steve.

[Cliff Ruggles]

Did you remove/clean or at least "rod" out the idle tubes during the rebuild?

Symptoms indicate not enough idle fuel so I'd start with the idle tubes and see if they are plugged or just too small for what you are doing.....Cliff