Eric English
February 17, 2010

The first generation of flatheads measured in at 221 cubes, but by the third distinct iteration from '49-'53, had grown to 255 cubes in Mercury form, and rated at 125 horsepower. Outclassed by modern overhead-valve V-8s which appeared in the '50s, the flathead largely faded from view for years, only to roar back to relevance in the last decade as rodders took a new interest in doing something different, and speed parts returned in abundance. Today, with bigger cubes, EFI, and superchargers available, alongside newly manufactured traditional speed parts, there has never been a better time to be a flathead fan!

289 Small-Block
If ever there was an engine associated with early Mustangs, it's the 289. We're not speaking solely of the High Performance K-code variants, rather all 289s down to the most mundane 200-horse two-barrel versions. Available into 1968, production of the 289 predated Mustang by more than a year, however the new ponycar platform literally accounted for hundreds of thousands of this small-inch Windsor. As such, they will forever be linked at the hip, each contributing to the other's ultimate success.

Of course the 289 proved a reliable workhorse on two fronts-the pedestrian everyday Ford, and the subject of our greater attention, high-performance applications. The K-code Hi-Po was built in limited quantities from 1963-1967, and featured beefier block hardware and a reciprocating assembly, along with a solid-lifter valvetrain. It's hard to say what kind of impact the engine might have had on motorsports if it hadn't been for Carroll Shelby, but together, the results were golden. Without a doubt, it was the Shelby connection which placed this small-block in the limelight, where it powered Cobras, G.T. 350s, and Trans-Am racers to a variety of championships. Prized today for their rarity and pedigree, the Hi-Po 289s remain one of our favorite V-8s of all time-and did we mention they're easy to work on?

427 FE Medium Riser
Why pick a particular variation of the 427 when we considered the 289 in all forms? For starters, there was no such thing as a pedestrian version of the high-minded 427, so there is really no opportunity to credit this engine for what it did for the masses. On the contrary, the 427 is solely about low production high-performance, and the Medium Riser was arguably the best iteration of the production versions.

We all know the story of the 427-how it was NASCAR-bred, became an instant drag race success, and powered Ford's ultimate muscle cars of the era. Early 427s were Low Risers, and then in 1964 came the "tall and terrible" High Risers that appeared in Thunderbolt Fairlanes and lightweight Galaxies. So what's the Medium Riser version all about? The MR was introduced in mid-1965, and like the 427s that came before, it's name stemmed from the rise (height) of the intake manifold. High Riser top ends were great for enabling the intake charge to have a near straight path to the valves, but were a race design that required a rather large 'scoop or bubble on the hood to clear the assembly.

As the name implies, the MR was a lower profile affair that actually tucked under the stock hoods of cars that could be factory opted with such engines (i.e. Galaxies, Fairlanes, and Comets). And yet despite being much friendlier for street applications, MR heads retained much of the flow of the High Risers, in part by using the same 2.195/1.733 valve package. Still, our pick of the MR as the ultimate production 427 stems from more than just the head/intake combo. Along with those impressive parts, the MR also benefited from Ford's new sideoiler block and forged steel crank. In short, it was a near bulletproof performer.