Double Pumper issues

[scuncio]

Hi all,

I have a 1972 vintage 700cfm double pumper on an LS5 El Camino. Runs well enough to have broken in the cam, but won't idle well unless I partially open the choke. If I take the choke off completely, it needs around 16 degrees of timing to idle (no vacuum advance). One other note: the idle speed seems to be inconsistent, and when I let off the throttle it takes a while to settle back to idle speed.


I have the mixture screw set to 1.5 turns, and just rebuilt this thing with one of Eric's basic kits. I assume this is user error on my part, but wondering if the symptoms point to something familiar.

Thanks!
Tony