Without the coolant temp sensor electrically hooked up, the PCM will interpret that as -40F outside air temperature, and try to compensate by making the mixture as rich as possible. Also,...Spun360 is correct in troubleshooting a stuck-open injector. Have you re-checked for,correct spark plug wire installation. A stuck open injector (electrical resistance), will not be any different than a properly operating injector. Try this, setup the injector electrical connectors to be easily removed from the injectors.,With the engine running at 1000 rpm approx.To get this lower idle speed create a small induction leak,by disconnection a small hose vacuum line.-,from the induction manifold source.The induction leak will offset the rich mixture-somewhat. Disconnect the injector electrical connector ,one at a time,noting which injector, when disconnected give NO change in RPM.This will identify which injector is stuck open. I'm not sure to what extent and how rich this problem is.. A fuel pressure gage when hooked up to the schrader test point will indicate a significant fuel press drop-off,after the fuel press rail has been pressurized, indicating a leaking injector. Propane that is delivered through a fine metering valve can get this engine to run at idle,with the fuel pump deactivated. these are troubleshooting ideas that you may be able to incorporate. hope any of these ideas help
1973 W-100 O/H 360' engine, w/a Edelbrock :1406 carb,2176 intake manifold, 2177 performer cam/ lift kit, Lokar cables, Dana 44 front axle ,A-727 auto-trans.Np-205 trans-case, Chrysler 8 3/4"SF rear axle ,All drum Brakes. Classic Auto Air-conditioner package.