Hi John:
Have you had any luck getting your Edelbrock carb adjusted? If not, why dont you compare your adjustment method with the standard Chevy method for the original Q-jet carb? Here is the method:
1. Get engine warm, make sure choke is fully open, air cleaner installed, air conditioning off, and put transmission in park or neutral. Make sure truck is on level surface and put on parking brake and block wheels for safety.
2. Set timing: pull vacuum hose from distributor and plug hose. If you have a fuel tank vapor cannister, disconnect the line from the tank. Then set timing to whatever it is for your model/year truck. Example: 8 degrees BTC. When this is done, leave the vacuum hose to distributor plugged and vapor cannister fuel tank line disconnected.
3. With engine off, turn in idle mixture screws full in CW until they stop and then turn out by 2 turns each. These are the two screws on front of carb at bottom of carb base.
4. Idle speed:Turn engine on and set idle speed to the idle speed specified for your model/year truck. Example: 700 RPM. On Q-jets, this idle speed screw is on the right side of the carb when facing the engine.
5. Idle mixture: Re-set idle speed to the MAX idle speed specified for your truck for lean drop idle mixture. Example: 875/700 RPM, use 875. Turn each of the idle mixture screws 1/8 of a turn sequentially while you are doing this step. Turn out (CCW) both screws (one at a time equally) by 1/8 of a turn until you achieve max engine rpm possible (or max vacuum possible) with just the mixture screws. Once this is done, reset the idle back to the 875 rpm with the idle speed screw if necessary. Then, sequentially turn in (CW) each of the mixture screws by 1/8 of a turn until the lower specified idle speed is achieved (700 rpm). If you have modest roughness in the idle at this point, you can back the mixture screws out a little bit each and equally until the roughness stops, then reset idle to specified 700 rpm with the idle speed screw.
6. Adjustment is complete, reconnect distributor vac line and fuel tank vapor line to vapor cannister.
*This procedure assumes the carb does not have a idle stop solenoid on the idle speed screw. It is a little different if you have one but I am assuming you dont. I am also assuming you have set your cold start choke beforehand per your Edelbrock instructions.
Good luck,
Henry