FrankenTruck F250?
 

So, first a little about the truck;

VIN: X26HKCE6339 Should be a 1978 F250 Supercab 4x4. The VIN matches on door and Frame.

The door plate says build date is 04/77 (seems a bit early for a 78, especially a 4x4 SCAB)

The VIN serial number build date says JUN 1978 (CE6339)

Everything on the truck is 77 with a few exceptions being: 351M w/ C6 and married T-Case. The neutral safety is 77 on the steering column. The truck has original paint in accordance with the door plate yet the hood, grill, lights etc are 77.

The truck looks completely original to include seats, headliner etc.

Do I own a FrankenTruck or a Ford excess 77 parts from the factory truck?

Maybe it was an early mule which somehow escaped the crusher, perhaps rescued by a Ford employee who would be able to pull that off...
Or the "4/77" is a typo.

I would agree on the typo except that everything on the truck is 77, except for married T-case

Late 77 and 78 F250's had married cases.

All 4wd supercab's were 78 and later vintage - no 77's.

Could your 78 have been built with 77 front rad support, grill shell, and column?

Hard to say. Seems unlikely for such key components and obvious external differences from what it was supposed to be, but I guess anything is possible.

The production date is printed on the Safety Standard Certification Label that is glued to the B pillar below the striker plate.

1978/79: The NSS is located on the transmission, C4 uses a different NSS than C6.

The hood is the same: 1973/79 F100/880 & 1978/79 Bronco.

X26 = F250 4WD Super Cab Pickup / H = 351M 2V / K = Kansas City MO Assembly Plant / CE6339 = 1978.

Compare the VIN on the Warranty Plate (riveted to the left door face below the latch) to the hidden frame VIN and registration VIN to see if they match.

People replaced damaged left doors with used doors. 99.9% of the time, they failed to install the original Warranty Plates on the replaced doors.

Yes the frame VIN and the door VIN match. The paint is original in accordance with the data plate paint code "F". So is it possible that this is a 77 SCAB 4x4?

My Dad always told me that if it looks, smells and tastes like poop its most likely poop.

F = 1977/78 F100/350: Dark Brown Metallic

If it looks like a duck and quacks like a duck, it's a duck, but in your case, it might be a goose.

It cannot be a 1977, since the last 6 digits of the VIN (serial number) are different.

1977 serial number range: O00,001-O99,999 & X80,001-Z25,000

1978 serial number range: AE0,001-CK9,999

Ford would not assemble a 1978 in April 1977. Does the VIN printed on the Certification Label match the other VIN's?

My truck has a Safety Standard Certification Label mfg date of 4/78 and VIN X26HKCA4274 So your truck was built in Kansas City shortly after mine and must have a typo. After all "quality is job one":-X04