Classic/Antique Car Repair: 73 ford ranchero, 351 cleveland, dieseling

Question
i have a 73 ford ranchero  with a 351 cleveland  and a 2 barrel   it tries to keep running after you turn the  key off it is like it wants to try to run but  cant i hope this enough information  for you  and thanks  for your time

Answer
That condition is called "dieseling". It is caused by excess gas being combusted by the heat of the exhaust. Three major causes are:

Being shutoff at excess rpm's
(Idle too high or other cause)

Timing

Bad valves.


There are other possibilties, but you should explore those 3 first.