Flathead Jack
Enter "Flathead" Jack Schafer. As a Flathead devotee, Jack is, by default, a bit of a curmudgeon. And as curmudgeons go, we begrudgingly admit he's frequently right. This is one of those cases. After working around the Flathead pumps' shortcomings, not the least of which includes the weak carbon seals and combination pitfalls, Jack did something seemingly impossible: He redesigned them. To top that, he had 'em cast in aluminum.
According to Jack, these pumps' computer-designed impellers move water more efficiently. Their radial-bearing-exclusive construction will take more belt tension than even the ball-bearing-equipped stock pumps. They also feature a completely redesigned and enclosed seal that reportedly bears contemporary coolant pressure levels without weeping or failing as the originals certainly will under similar circumstances.
Jack offers these pumps in two basic body designs, each with two subsets. The first design fits '37-48 engines, and as such lacks the bypass configuration. The second design fits '49-and-later engines, and as such features the appropriate bypass. It's the two subsets that really make these pumps shine, though; both body styles are available with single-sheave aluminum pulleys in a choice of the early or late pulley offset.
Above and beyond having really beautiful pumps, it means early-engine adherents don't have to endure irrelevant and awkward-looking bypass ports on their engines. What's even more important than that, however, is the fact that late-engine devotees don't have to forsake the bypass design or the improved impellers to use crab-type ignition systems.
 Flathead Jack's WP-59A pumps...  Flathead Jack's WP-59A pumps are direct replacements for all '48-and-earlier passenger car/pickup engines (single-sheave-pulley only). |  As its name suggests, the...  As its name suggests, the WP-59B is a hybrid; it's the same pump body as the WP-59A, but it uses aluminum renditions of the '49-and-later-style pulleys. |  Knowing these pumps would...  Knowing these pumps would create demand for the appropriate crank pulleys, which are already in short supply, Jack tooled up to machine these aluminum pulleys. |
 WP-8BA is also a replacement-style...  WP-8BA is also a replacement-style pump, albeit for the '49-and-later engine. |  Flathead Jack also offers...  Flathead Jack also offers iron-bodied replacement-style pumps. |  Now here's the real problem-solver....  Now here's the real problem-solver. It, too, is a hybrid like the WP-59-B; however-and probably most importantly-it's a hybrid in the other direction. |
Speedway Motors
Recently, "Speedy" Bill Smith incorporated improved bearings and seals in several popular pump styles. He has them cast from a high-nickel iron and spot-faces the fastener-mating surfaces to ensure proper contact.
While Speedway retained many of the stock design elements, including the six-blade-straight impeller for the early pump and the belt configurations, all boast tighter internal tolerances, combination roller/ball shaft bearings in lieu of all-ball bearings or bushings, and improved ceramic seals, the latter reportedly similar to those used in Nextel Cup race car pumps.
Even though Speedway doesn't offer a modified version of the '49-52 Mercury pump with the raised mounting pad, it does offer modified versions based on the '49-and-later Ford and '53 Mercury truck pumps in either wide or narrow pulley configurations.
 Speedway's 91015593-DRV &...  Speedway's 91015593-DRV & PASS pumps are 78-series since they feature rear-offset, wide-belt pulleys and mount early engines or plugged-block late engines in all '32-48 trucks up to 1952. |  While the 91015592-DRV & PASS...  While the 91015592-DRV & PASS pumps retain the 8RT's bypass configuration and forward-offset, wide-belt pulleys, they feature improved bearings and seals. |  Speedway also offers improved...  Speedway also offers improved pump designs for '49-and-later Ford cars, '53 pickups/trucks, and Mercury cars. |
Cornhusker Pumps
While Flathead Jack and Speedway retained the design attendant to all Ford Flathead engines, Gary Mussman at Cornhusker Rod & Custom bypassed the design altogether. Make no mistake; this kit visually transforms the feel of the venerable Flathead.
Cornhusker's conversion doesn't use two pumps; it uses one, la overhead-engine design. Ironically, it isn't even a Ford unit; it's the pump Chevrolet used on its own '58-65 348 and 409 engines. In fact, it even uses small-block Chevrolet pulleys.
These bolt-on kits include a brand-new pump on an outright basis, adapters, hardware, gaskets, and instructions. While the kit is an entirely bolt-on affair, the optional bushing kit to mount the engine higher in the chassis requires welding brackets to boxed framerails. While Cornhusker offers kits to fit various stock Ford and hot rod applications, its versatility is limited only to a builder's imagination and fabrication skills.
Since this pump features conventional late-model seals and bearings, it'll withstand conventional belt tension and coolant pressures; however, the adapters don't accommodate the late-engine coolant bypass function.
 Cornhusker's kit is an entirely...  Cornhusker's kit is an entirely bolt-on affair that includes billet adapters and steel-sleeved, billet-aluminum lower crank hub and single- or double-sheave pulleys. |  This pump assembly offers...  This pump assembly offers a choice of either an alternator exclusively (lower right) or an alternator and A/C pump bracket (upper left). |  The standard bolt-on assembly...  The standard bolt-on assembly features these combination pump adapters/engine mounts. |