Engine problems: Any advice?

[Gaz64]

Originally Posted by jhv48

Tim, you left out one detail that you included in your SCOF thread. The vacuum secondaries in your carb have the stiffest spring (black) that Holley makes. With these light cars, they need a mid pack spring at least, as they are so light.

Before you mess with anything else, get the mid tension spring and see what happens. Your symptoms are that of a car whose secondaries are not opening.

Secondaries not operating would make the engine lay over but not spit and cough etc as described.
Effectively you have a 390 2 barrel (half of 780 cfm).

Check the float levels, I'd bet on a stuck secondary needle and seat.

By all means change that spring to a green, red, or a long yellow.