I have a 76 f150, 360 and everytime it fails the emmision test's. It's not burning enough fuel to pass under the load test. I've already changed plugs, wires, cap, rotor, and I have the carb tuned as lean as possible by adjustment the screws on the passenger side of the carb and It STILL fails... any help would be greatly appreciated! Thank you

 

Guess I should be sleeping instead of being here as your comments are confusing me. You are leaning out the mixture screws when the truck is running lean. Fatten up that puppy, check your float adjustment, could be to low. Post up the actual results, HC and CO for idle and for high speed.

 

I may have misworded the problem, I have a bad habbit of that haha There is too much unburnt fuel in the exhaust vapors for it to pass emissions. I need to figure out how to get it to burn more fuel from the mix, if I make it rich will it do this? This is very confusing for meff

 

Air flow, not enough air to mix it properly. Spark Gap, not enough spark to ignite fully. Timing, not giving it enough time to burn off fully. Engine misfire, make sure all spark plugs are gaped properly (.44?) and spark plug wires fully seated and check Firing order, make sure you have all spark plug wires where they are supposed to be. Carb Float, check for proper operation by seeing if it is cracked and filled with gas.

These are all things you can check.

 

Also make sure your truck is up to temp, at least 200' on the water and a fresh oil change can help.