l just bought this 1985 F350,crewcab/flatbed duelly with auto/460.Great truck,love it.Previous owner just had heads done,timing chain and new carb.l noticed l couldn`t give it full throttle,it would just bog,and upon examination found it to have incorrect carb.l replaced with factory reman.lt idles well but seems to run way too rich and won`t run well at all if l put the air cleaner on.l found the timing to be retarded and the advance ported at the wrong place so l set the timing with a vacuum guage and fixed the dist.vacuum line.lt`s better but still seems to be loading up really bad and runs WAY better with the air cleaner off.There is no interference of linkage being caused by the air cleaner assy.,that was the first thing l checked.Fuel pump is stock,oil pressure good,doesn`t get hot...l haven`t put a timing light on it yet though and l know l have to do that next...l think with the timing so out of whack the power valve was allowing fuel to dump and causing the rich condition...any ideas anyone? any help appreciated

 

Because you say you checked everything, this probably isn't it, but. . . I had an '81 F250 w/ a 400 w/Edelbrock 4 BBL. I put an aftermarket open element air cleaner assy on it and had a similar problem. After an hour of head scratching, I found the bottom of the air cleaner lid was just barely pinching the fuel line, causing the sucker to run dry under full throttle. At part throttle, it could supply enough fuel to keep things smooth. Got a different air cleaner base and things were great thereafter. . .

I know, probably not your problem, but thought I'd share it since you mentioned you checked clearances to the linkages, but didn't mention clearance to the fuel/vacuum lines. . .

 

The stock air cleaners are way too restrictive, so replace with an open element K&N or equivelent.

 

thanks guys,good advice.l will check the fuel lines tomorrow.l seem to remember a kink in the metal line near the carb and l didn`t think it was bad enough to cause a problem but l`ll fix that.l really think l`m getting enough fuel though...