I have a 1961 Chevy " Apache" Fleetside Pickup with a 283 V8, manual choke, that won't idle even after purchasing and installing a new Carburetor. Engine runs at high RPM's and compression test on first plug shows 160 instead of the manufacturer's recommended 140. Didn't check other plugs for compression. Take foot off accelerator and the engine sputters and dies.
Put the fast idle screw on the 2nd step on the fast idle cam-raise the rpm to atleast 1200 by turning the screw for it. Snap the throttle, it will drop to base idle if not adjust it. Find the mix screws-close it and back it out 2 turns for both. Now try to set the idle at 650- now go back to the mix screws start closing it when you feel the engine misfiring back it out 1/4 turn, do the same for the other screw then readjust the curb idle screw till you get to 650 or 750.
Are you time properly? You need to get the idle properly before you time it then readjust the idel again.
Also won't hurt to check the fuel pump pressure and PCV valve.