Just swapped the engine on my '64 F250, which previously held a worn FE in place of the original 292.
I am trying to ID the engine that came out. I know there is not much way of telling displacement without pulling the oil pan, which I don't want to do since the is going into storage and I prefer it to stay sealed.
From the top down, it has a 2bbl C3AE manifold (original 292 carb on it). Valve covers are Mercury round tops, similar to the early 390 Thunderbird covers. Double valve springs on C1AE heads. Exhaust manifolds are C3SE log style. Couldn't find a casting number on the block. Clutch is a 13in unit with C7TE pressure plate and the flywheel is much thicker than the 1967 352 I had to compare to. There are no casting numbers that I saw on the block, but the PCV is the old style. Hydraulic cam.
The original owner said the engine was from a '63 Merc, pulled used from the junkyard. Did Merc offer 352 in '63? I know Ford did. But the double valve springs make me wonder if it's a 390. The heads had the original FoMoCo valve seals when I replaced them several years ago, so I don't think they've been touched.
Any opinions welcome!

 

No Mercury car came with a 352.

1961/64 embossed MERCURY 390 valve covers are rounded without holes for smog valve or oil cap, there's an engine oil fill tube on the right (passenger) side of the engine block.

Similar valve covers were also installed on the following:

390's installed in 1961/64 Ford & Thunderbird are embossed THUNDERBIRD, 352's installed in 1961/64 Ford's are embossed FORD.

1962/63 406 & 1963/64 427 valve covers were plain.

 

Thank you. I always assumed a 390, but the 2bbl threw me off. The 352 is much more lively than the 390. I should mention the 390 had compression that ranged from 50-100psi, with everything in between. It was indeed well worn.