I have a 1975 F750 with a 391 eng, 4brl holly, and that darned governed distributor. Does anyone have any pics or can you tell me the ways to do a way with that governed business. Truck runs great at idle but when you get it mid way it does nothing but miss and cut out. Driving me nuts. Engine doesn't have many miles on it but just can not get it to run smooth. Played with the timing, ect. No luck.

 

From what I've heard, you can modify a regular 390 car or pickup distributor to work, but if I remember correctly you'd have to make a bushing to get it to fit right.

I'm sure someone else on here has a better description of how to do it, they'll probably be around soon.

Sam

 

A bushing was available from Ford, not sure where to send you:

332-428 Ford FE Engine Forum: FT block distributor bushing

Here you go:

390/391/427- Ford FT to FE distributor bushing | eBay

 

Getting it midway it flats out? Sounds like the gov. is working, but I dont
know what rpms it is when it does it. It may have to be turned up a little.
I recomend not going over 3,000 rpms, I dont care what the book says.
As far as running ok at idle and lousey at higher rpms, It maybe advanced
to much. This setup does not like it cause the mechanical weights in the
distrubutor does it. If not many things, weak coil, weak resistor, weak
condenser, points closed, weak valve springs, blown power valve and
the list goes on. Governor issues have no effect with running smooth.
Usually bad vacumm effects idle reel bad, I dont think thats it. Again if it
purrs at idle and runs rugged racing it up thats usually over advanced.
Then if you must disable the governor (I dont recomend) just remove the
line from the dist. to the gov on the carb. do not plug this fitting on the
carb. because if it is plugged you will have no throttle at all. To adjust the
gov.rpms, on the dist, remove the square plug (it has a rubber line going
to the carb drivers side) after that turn engine over by the fan until
the gov and shaft revolves around until you see the adjustment screw or
some have an allen, slightly turn clockwise to increase rpm and counter
clockwise to decrease rpms. Again over the years I have found simple
things like a week condense can drive one bonkers. Like for example,
you want to drive somebody or an enemy nuts? Just write on his
distrubutor cap with a lead pencil. They will never find it, that was an
old 1950s prank. I have 100% luck with all my 391s . One more thing,
they absolutly do not like cold raw damp weather, the carb base will
frost up, it wont throttle up, black smoke. I find letting it run this way
it will finally die out. Shut key off walk away for a while letting the small
amount of engine heat, then it will run fine. Sam
]

 

The point plate wears out and causes eratic dwell and timing, this may be some of your problem. Converting from points to electronics , such as Pertronics usually helps quite a bit. Check the shaft for play as the shaft bushings may be worn. A govenor on these motors is a engine saver as too many RPM's will kill it. If you disable the govenor get a tach and keep the R's below 3500. Running the engine at higher speeds will not help as the cam is all in by 3/3500 rpms .

Have A Great Day ------- Hotwrench

 

Thanks Hotwrench, I forgot to mention that, cause I had one of my trucks do that and
got a rebuilt from Napa.

 

sounds like something a 3208 cat would fix. Engine really doesn't have many mile on it, hours not sure of as it use to be a pumper truck. Only has 13k miles on it. Thinking about just selling or parting the old girl out and just go back to a one ton. Doors are like new on it. I put a 10ft flatbed on it. Actually don't need that big of a truck.

 

We had a 71' C-750 5/2,,that truck ran awsome,,,would drive away from IH 1700's with the same basic loads,,(2 junk cars on each)make sure the right spark plugs are in the engine,,,Motorcrafts or Autolights,,,No Champions ,,,to hot of a plug will cause the engine to pop and sputter at higher RPM,,,with only 13k on the truck if it's all original, cant really see how the dist would be worn out ??, Our 71' had approx 100k on it(dont recall exactly, was a old Lehigh Gas Propane truck)
Someone mentioned the carb, powervalve, seems to me a higher RPM Backfire or cough can takeout a carbs powervalve, this could be a problem ?
A Bad Condenser can make it pop and backfire,,with that 391 running good,,you would be happy,,,maybe the 71' 391 had more compression then a 75',, But it should run Good ! Good Luck ,,sounds like a nice truck