I just got done with replacing the head gaskets on my 83 351W Bronco, I'm pretty sure all the vacuum is hooked up right (no sticker, had to research online) and it runs well, but if I'm sitting in P or N, if I floor the gas real quick and let off it idles rough and if I am in D or R and I do the same (brake on) it will die or act like it's going to die.

All vacuum is hooked up, I had an intake leak but sealed that off, all emissions equipment is working correctly (to my knowledge).

The only thing I can think of is that it's the carb. It's got a Holley 2bbl on there and it looks fairly old. I can't find any other numbers on it other than "1024" and the next line below it has a 5 digit number starting with 9. I am not sure which model this is but could I be correct in thinking that it needs a rebuilt or replacement? Should I have done any adjusting when I put it back on after my work on the upper end of this motor? No adjusting screws were touched in the process.

One problem I had was not downshifting when I gassed it going about 20 MPH but I had two vacuum lines going to a T from the carb, and they are supposed to be connected to a TAD/TAB solenoid (was going to the automatic choke, choke should have been going to manifold vacuum according to diagram) and after I corrected that it seemed to shift correctly, I have the same problem before and after I made this change.

Again, this is an 83 351W with EEC-III Duraspark III ignition.
New wires/plugs, rotor and cap are fairly new, runs like a champ otherwise. No hesitation or backfiring.

Thanks in advance!

 

It might be as simple as an out of adjustment or non-functioning dashpot. Its function is to cushion the throttle return so the engines doesn't stall when the throttle is released too quickly.

Or, it may indeed be time for a rebuild. Holleys have their identification numbers stamped on the airhorn:



You're looking for a either a List number (it'll say the word "List" followed by a number) or a Ford part number. From there you can get a rebuild kit. If all else fails, take the carb into the local auto parts store (if you have one staffed by people who know what they're doing, so that pretty much eliminates most Autozone or Kragen's) and see if they can figure it out from the numbers on the carb. They should have it by application if this is the original carb.