I have a 1986 F350 with a 460. After i bought it i found that it was not the original engine. Most of the anti pollution equipment was taken off of it and it ran like crap. I put new heads on it and although it still has good power it idles badly. The Carb is a 2bbl which is clearly the wrong one. It has a manual choke and once it warms up, the idle is all over the place, it idles high, then low, them pulses from high to low.

Last year i bought a rebuilt 4bbl carb from national carburetor, with that the truck ran even worse. Every time i hit the gas, the truck would bog horribly. I called them and they sent me the parts to repair the accelerator pump but that did not help so i sent the carb back.

One if the biggest issues i have is all of the vacuum lines. There is so much stuff missing on the engine that there is no way to properly connect all of the vacuum lines. What i tried to do is just block off everything except the timing advance figuring the engine should at least run. This is with the new carb as well as the old. The new carb had float bowl vents that i simply blocked off. Im wondering if this was causing the bogging out when i would accelerate. I need to do something to make this truck usable.

Any thoughts are appreciated.

 

I don't want to offend you, but it sounds like this job may be over your head, technically. There is no engine that you can just bolt a random carb on and expect it to fix your problems.

 

Start by connecting a vacuum gauge to the intake manifold. How much vacuum do you have at idle? Should be better than 18" Hg, and the needle should be steady. Then with the air cleaner removed and the engine running use a mirror to look down the throat of the carburetor. Idling and with the throttle slightly open you shouldn't be able to see any droplets of gas. If you see droplets the carb isn't working correctly. You should see a squirt of gas when you open the throttle but it should stop when you hold the throttle still.

If you don't see droplets try adjusting the idle mixture screws.

Pull all the spark plugs and look to see if they are fouled with a black soot. That would be from poor combustion. White soot would be from coolant getting into the combustion chambers. While the spark plugs are out you should do a compression test. Spark plugs are cheap, put a new set in gapped to the proper size.

First you need to know if the engine can run properly before you try tuning it.