1966 F-350?

Advert says F-550. Note that it has the 300 six cylinder. Also say "automatic", but I believe it to be manual transmission.

https://www.facebook.com/marketplace/item/3457034017908186/?ref=browse_tab&referral_code=marketplace_general&referral_story_type=general&tracking=%7B%22qid%22%3A%22-3818927617166657442%22%2C%22mf_story_key%22%3A%2236368225290789899%22%2C%22commerce_rank_obj%22%3A%22%7B%5C%22target_id%5C%22%3A36368225290789899%2C%5C%22target_type%5C%22%3A6%2C%5C%22primary_position%5C%22%3A12%2C%5C%22ranking_signature%5C%22%3A5106888128384204800%2C%5C%22commerce_channel%5C%22%3A501%2C%5C%22value%5C%22%3A0.00047654668350342%2C%5C%22upsell_type%5C%22%3A129%2C%5C%22candidate_retrieval_source_map%5C%22%3A%7B%5C%226282616485152849%5C%22%3A3001%2C%5C%226257926964242714%5C%22%3A3012%2C%5C%226217172215017266%5C%22%3A801%2C%5C%226290773684374394%5C%22%3A3002%2C%5C%229434080436662523%5C%22%3A3003%2C%5C%226280262268736215%5C%22%3A3501%7D%2C%5C%22grouping_info%5C%22%3Anull%7D%22%2C%22lightning_feed_qid%22%3A%22-3818928716663417157%22%2C%22lightning_feed_ranking_signature%22%3A%224470073250096873472%22%2C%22ftmd_400706%22%3A%22111112l%22%7D

Yes, I think that may be an F350 not a 550.

Wikipedia says this about the 1965/66 models:

In October 1964, the 1965 F-Series introduced an all-new frame, which would be used on the F-Series through 1979. The body itself remained largely unchanged, but on 1965 and 1966 models the turn signals are above the headlights. Replacing the rudimentary straight-axle in the front was all-new independent "Twin I-Beam" suspension with coil springs on two-wheel-drive trucks.[4] The change in suspension also lengthened wheelbases slightly. 1965 and 1966 F-Series trucks are distinguished with a "TWIN I-BEAM" emblem on the front fender. A 4-door crew cab was also introduced on F-250 and F-350 models.

The 240 cu in (3.9 L) and 300 cu in (4.9 L) straight six was introduced. With the introduction of the 208 hp (155 kW; 211 PS) 352 cu in (5.8 L) FE V8, output surpassed 200 hp in the F-Series for the first time.

So both the Twin I-Beam and the 300 six were introduced then.  

Hmmm, this might be a good water hauler for Jonathan Donald in AZ???

Good looking truck!

Edit: when I looked at the post it said that a F550 rear end was put in it.

It's got the fat front fenders of the F-500/600, as well as the Fender lights that the Medium Duty F-series got. The Fenders are "Fatter" to allow for the larger tires the F-500/up got.

So I would say it's a F-500 by the picture. But not a automatic...


Here is another picture of a 1965 F-500 with "Fat" fenders.





Then a picture of a 66 F-350 Dually.  Notice the fenders are not "Fat".

David - Interesting!  I've tagged Jonathan.

Dane - I guess that's why it is listed that way?  

Thank you David and Gary! This is a great old truck. I was actually looking at an older “Fridge” body style F600 as a water hauler but it said it needed brake work and from what I found online those parts are unobtainium. Definitely fabrication/adaptation territory and I decided that was a headache I could do without. But here I am years later and the truck I DID buy is still waiting for its engine transplant 🫤. Maybe the brake parts would have been easier…

I like the Jeepers Creepers plate.