This is kind of getting beaten to death. The C-code, 200hp 2bbl 289 came out in mid-'63. Mercury often tried to have somewhat unique powertrain options (like the 390 2bbl motors that Fords didn't have, or the 410FE, a Mercury-only engine that was basically a 390 bore with a 428 crank). They took the C-code regular fuel 289 and put the existing HiPo intake and a 4bbl carb on it for use in their cars in 1964. This created a 210hp engine that had the same long block as the C-code 2bbl engine. For reasons known only to them, they assigned this motor a "K" designation, even though sister company Ford had already been using that letter designation since mid '63 in HiPo 271hp solid lifter Fairlanes. In Mercury shop manuals, they show 271hp engines available in the Comet line with a "D" as the fifth digit of the VIN. However, no '64 Comets with "D" codes have ever surfaced. Those '64 Comets documented as original 271hp cars all have "F" (260 2bbl) or "K" (210hp 289) codes in their VINS with build sheets listing "HI PERF" conversions, so they were likely pulled from the line after being started as non-Hipo builds.
This is confusing because Ford consistently used the K code for 271hp applications from 1963-1967. They also decided to use the Mercury-spec'd 210hp 4bbl 289 later in 1964 and assigned it a D code, which was installed in Fairlanes and very early 1965 Mustangs (aka 64-1/2's). Thus (in the shop manuals at least) 1964 Comets had the EXACT OPPOSITE nomenclature as 1964 Fairlanes in regards to the 271hp and 210hp 289 engines.
Anyone who wanted a regular fuel 4bbl 289 in their 1964 Comet got a K coded VIN, so many thousands were made, with 3speeds, 4speeds, and automatics using 8" rearends. A very few of these might have been converted to 271hp status, but they would have to be 4 speed cars with 9" rearends and would need DOCUMENTATION to be considered real. Conversely, if you have a K-code Ford product from 1964, its certainly a 271hp HiPo car.
They got their letters aligned for '65, so this confusion doesn't come up that year.
Is the mud a little clearer now?
