I couldn't find any other tag until I starting scrubbing.

 

Yes, that label!!!!!

Watch this space.................

 

OK, no real help here (well, see below), I tried.....

That sticker tells me your Basic Engine Code is 890 but nowhere can I find what that code (or any code, for that matter) translates to.

Most helpful thing I can find in the FoMoCo parts catalog is:

"Current production engine assemblies may be ordered from the local parts distribution center by furnishing the engine code from the vehicle certification label or the identification tag number that is attached to the exterior of the engine assembly."

*sigh*

That's OK, though, because this stuff doesn't definitively tell us anything; quite honestly, the best way of identifying it is going to be the casting codes of the block itself.

Problem is, this engine was in production for only two years and information about it on the 'net is pretty scarce.

So, even if you crawled under there and got the casting code, I don't know of any online information about that engine where you could verify anything.

Unless somebody else can come up with something more, I think the best you can do is look at the information available to you (which says it's a 4.2L) and look at the engine itself which to me looks pretty much stock, there's a good chance in my mind it's the original engine. It's not definitive but I don't know what else to tell ya.


Well, ok, here's something that might help verify some more.....


On the right side of that sticker are some more letters, tell me what is to the right of the "C" character there (below that is R, below that is S). That's your Calibration Number, from there I can find the Parts List Number, which gives me the part numbers of various fuel, ignition & emissions-related components. I guess there is a chance that one of those components is for the 255 only and not also the 302......?


Well, at least I *THINK* I can cross-reference this stuff, but I should give a disclaimer that I can't guarantee it.

 

Actually, I just found it in the parts book...

Turns out there is only ONE calibration code for a 1981 F100 with the 255 engine and with an automatic transmission.

Your Calibration Code is 1-58G-R0.

OK, lemme look around some more....

 

OK, how's this....

I don't even have to go look up specific parts, it tells us this Calibration Code belongs exclusively to a 1981 F100 with the 255 engine and automatic transmission:
.
.

 

And, here is something else you can do....

Look in that List No. 105 list, on the RH side specifically....

Scroll down through that list and look for the pound sign (#) followed by a code....

That code (part number) is the Engineering ID Number that is stamped or embossed onto the part in question.


So, for example, go look at your smog pump, see if you can find one of those E0BE or E1TE numbers on it (a comma in this description means "or" so, for example, the part will end in A1A or A2A).

 

Thanks for all the information. You are correct, to the right of the "C" I have 58. There is blue over spray over the last character so I cannot tell if it is a "G".

I am convinced, given all the facts, this is the original 2.4L.

Thanks again.