I have an 81 351W powered c6 bronco with 3.50 gears. It is a gutless POS. I know the carb is the problem. I'm lead to believe that originally it had a VVC (Variable Venturi Carb) but now has a Holley two barrel with a lot of 1st generation smog crap. It has no power, dies all the time and is just generally undrivable for anyone but me. Even then I have to restart it from time to time. I have a solid front end for it, an aod (Ford reman) and better gears but the way it runs it's not worth it.
Can anyone shed any light on this POS fuel system? Any options?

 

If you say it's the Holley, then tune, rebuild or substitute it, whatever fits your needs. I usually would go against taking smog stuff out, but do some research on it, most of it can be taken out without any issues whatsoever (easier than on EFI systems anyway). I would also check the ignition to see what's going on there, and what's the condition of everything. Is the timing set right? it should be at or a little above 10 degrees BTDC, and the sparkplugs gapped at at least 0.042 up to 0.055. How is your exhaust? what is your setup there?.

 

Early emissions is generally an easier set of equipment to "get around" simply because it isn't nearly as well integrated as it is in the EFI-equipped trucks. The VVC's were crap but I'm not sure the Holley was the best thing to replace it. (Never liked Holleys myself... I mean who uses compressed paper gaskets to seal vertical seams in a fuel bowl? Oh wait Holley does!... off soapbox). Encho already mentioned a good number of things to inspect. I would add that the issues you are describing are all typically related to a truck/engine that just hasn't been properly or regularly maintained. Doesn't sound like you have been in possession of this truck for that long and perhaps the PO didn't know much about routine maintenance.

 

My 83 302 had the Motorcraft 2100 2 V carb. I rebuilt it and found the power valve stuck. Once rebuilt it was fine. I did have to replace the ignition module a couple of times and kept a spare in the truck.
regards
rikard

 

Make sure you don't have any vacuum leaks, borrow or rent a gauge if you can. Poor idle, dying and low on power could all be caused by a vacuum leak and it's something that's easy/cheap to check and fix. Look for any cracked hoses and spray carb cleaner, WD 40 or something along those lines anywhere there could be a leak, if the idle suddenly smooths out for a moment, you've found it. I've bought several trucks cheap with leaks that the owner had replaced all the usual tune up parts only to get frustrated and give up.