First, it's a cheby. Dump the engine and get a Ford.
The thread does not have enough information to really help.
What is the carb number?
What work has been done to the carb?
What work has been done to the engine?
Was or has the card ever run correctly?
Is it a new or used carb?
What is the vac of the engine at idle and at 2500/2800 Rs?
There is a cork or black material gasket that interfaces the vac sec to the throttle body. Is that gasket in place and sealed to work? Makes all the difference in the world.
With the vac sec off the throttle body, can you activate the diaphram with a minivac? If not the seal/diaphram/pan is/are bad.
What are your capabilities? Sometimes a fresh face looking at the same problem may be able to see an error. Can you have a friend look it over that is knowledgable... and can spell?
