383 Wont Idle with new to me 800cfm DP. Idles and runs ok with Edelbrock/AFB

Thanks for the advice guys. I was trying to get the timing at different rpms last night and my timing light started acting stupid. I have a Mac tools digital dial back to 0 timing light. I set rpm at 2500 rpm and 33 advanced as I did before. I went to bump the throttle to 3000 and the timing light was instantly set on 45. I did not move it. I relived the mark back up and it said 50. I brought it back to idle and had 33 at idle. Mind you I am not hitting the adjust button on the timing light. I will grab my old rotary dial and recheck.
As far as the carburetor, I have the secondaries acting as an air bleed which is what drilling holes in the primaries would do and I am able to completely close the primaries which in my mind should allow the mixture screws to work. They do not have any effect. I need to make sure the mixture ports are completely clear. Maybe try another metering block off of another carb I have laying around? I will post what I find. I am back at work now though so it will be late tonight


The engine idles off the secondary side as well. Jacking the secondaries open is just as bad as jacking the primaries open. Like I said, you may need holes as big as .187 in each primary butterfly. They are cheap. Buy two new ones and drill them. If you still don't like the carb, put the original ones back in.

If you are jacking the secondaries open to close the primaries you just robbed Peter to pay Paul.

Edit: don't swap metering blocks from different carbs. The emulsion can be different, and all that affects air bleed calibration and other stuff.