I have a 1977 Ford F-350 Crewcab. It has a 460 V-8 with a carter 750 cfm 4brl Carb. The engine will start and idle (not very well). When the Choke opens up it dies. I have blocked off all Vacum. It has new plugs wires points cap and rotor. The carb is new. I have checked and recheckd everything. The engine as far as i can tell is from a 1974 Lincoln. It no longer has duraspark ignition the previous owner installed a points distributor. I am unsure at what to set the plug gap and point gap a 1970 Lincon calls for .034 on the plug gap and .017 on the points. My Haynes truck manual calls for the plugs to be gapped at .044 for 1977 however this would have duraspark ignition. It will aslo back fire through the carb if you flutter the throttle to keep it from dying . Any thoughts or suggestions.

 

A vacuum leak is what is causing your problem.

 

Thats what evey one says However I can not find any I have removed all vaccum circuts and pluged the holes start the engine up and spray carb cleaner over the intake and around the carb and the idle does not move.

 

Has the intake been off? It could be sucking air from the underside of the intake in the valley.

 

The problems are in the Carb. This morning I decided to try another Carb on the engine and it will idle now. I also found out that I had the plugs gapped wrong. The 1974 Lincon engine calls for .054. Whereas I had set them at .044. Every other year in the 70's calls for .034 or .044 and I got the off year. I took the Carb in to have it checked out and find out whats causing this so hopefully I will have it back together and running smooth Monday when I get my Carb back. Thanks for the help.