Jim Smart
July 18, 2014

Few can dispute the FE series big-block's performance on a grand scale. This is the legendary engine that not only won Le Mans, it spanked Ferrari and other exotics in a global venue only the very few get to attend let alone win. Ford won Le Mans via the University of Hard Knocks. It took Ford years of trial and error to get the FE big-block where it needed to be to win.

To win, an engine has to stay together and actually finish a race. The FE's largest shortcoming early on was shaking itself apart. Main caps that worked loose in stock car racing—scattering iron, steel, aluminum, oil, and coolant all over tracks from coast to coast. Ford engineers kept the dynamometer labs roaring searching for the FE's biggest weaknesses. Some of the greatest weaknesses were main caps, block webs, and lubrication issues. In 1962, Ford developed 406 and 427 blocks with cross-bolted main caps in order to provide down under security. The cross-bolted main cap block was a fresh iron casting ready for thrashing and trashing on the racing circuit. Racers welcomed the new 406/427 cross-bolt block and put it to work. Though the cranks stayed put, they burned up and failed nonetheless. The new 427 struggled to finish a race because it had trouble keeping an oil wedge between moving parts at high rpm.

At the time Ford engineers were birthing the 427 Single Overhead Cam (SOHC) for NASCAR use (poo-pooed by NASCAR authorities), they were also developing a better 427 cross-bolt block known to most of us as the side oiler. The side oiler vastly improved oil distribution throughout the 427 with great focus on main and rod journals. With the bottom end sewed up tight with plenty of lubrication for thirsty main and rod journals, the 427 was ready to meet the stressful world of endurance racing.

Bear Market

For years, Ford 427 parts of any kind have been scarce and expensive. If you've needed a 427 side oiler block, you'd better have a Ford E-Series van full of cash to bring one home. And a new old stock side oiler? Forget it.

Imagine if you could sit down at your PC and order a new 427 side oiler block authentic in every way produced using the most advanced casting techniques in the world. And imagine a side oiler block you could actually afford. Bear Block Motors introduces the 427 side oiler block for your dreamy FE big-block project. Imagine being able to build an all-new FE big-block using one of today's stroker kits and the 427's huge bores along with roller cam and high-tech cylinder heads. Bear Block Motors not only offers you the block, it has also engineered high-swirl heads to go with the block.

01. Meet the new kid—yet old kid—on the block. The clean-shaven 427 cross-bolt side-oiler block from Bear Block Motors and Blue Oval Performance Engineering. Even if you have an old side oiler block, put that guy away for safe keeping and check out Bear Block Motors’ new 427 casting. Casting technology in Ford foundries was never this good 50 years ago. The Bear 427 block employs diesel-grade iron with improved oil circuitry, thicker main webs and 0.750-inch decks, and perfect-fit cross-bolted main caps void of spacers. Big bores are 4.245-inches, finished to 4.250-inches. An optional 4.180-inch bore is also available. Weight is 250 pounds including steel main caps.

02. Check out the buttery smooth machine work displayed here. All mating surfaces make for perfect gasket contact and leak resistance. Oil galleys are all screw-in plug.

03. The 427 side oiler from Bear Block Motors has advanced oiling system circuitry with larger galleys for volume aplenty.

04. What makes the Bear 427 different from Ford’s vintage side oiler is hydraulic lifter capability. You can run flat tappet or roller hydraulic lifters in this 427 block.

05. Cross-bolted main caps are a perfect interference fit between the block skirts and without spacers. Locating dowels in the main saddles “lock” the forged and heat-treated 8620 steel main caps in place.

06. Look at the casting and machining quality demonstrated here with screw-in freeze plugs and the correct C5AE-H casting number.

07. The Bear 427 looks great from any angle thanks to advanced casting and machining techniques. Once you have your Bear 427 in paint, it is virtually impossible to tell the difference between original equipment and the Bear 427.

08. The Bear 427’s lifter valley sports abundant webbing for extraordinary strength. Classic 427 blocks were never this good.

09. This is the Bear aluminum 427 block tipping the scales at 125 pounds. Like the iron block, casting and machining quality are over the top.

10. Valley webbing is extra thick making the FE aluminum block a cut above and born for the business of high-performance driving. Check out the casting thickness around those lifter bores with no worries about core shift.

Aluminum Block

If lightweight aluminum is more to your liking, Bear Block Motors has your FE block. In paint, it is challenging to tell the Bear aluminum 427 block from iron because it is cast basically the same way cosmetically with all of the correct markings. It weighs just 125 pounds, remarkable when you consider the weight of an iron block at 250. What's more, the Bear aluminum FE block is priced just $1,200 higher than the iron, which is somewhere around four grand. If you perceive the new FE as pricy, price a used 427 side oiler block and be ready for sticker shock. Prices on both iron and aluminum blocks have not yet been confirmed.

On Top…

With such a grand slam block casting for FE enthusiasts, you'd expect Bear Block Motors to complement this block with a world-class cylinder head. It has with the high-swirl aluminum FE cylinder head in as cast and machined or in CNC ported. This is the FE cylinder heads brought to current engineering standard high swirl, good quench 72cc chambers, 11⁄32-inch valve stems, 2.150/1.680-inch intake/exhaust valves, 300/225cfm intake and exhaust volume, and bowls cast to match valve seats perfectly. Extra thick port walls allow for additional porting if desired.

There's also a CNC-ported FE head available from Bear Block Motors with 2.250/1.750-inch intake/exhaust valve sizing that offering a whopping 355/250cfm intake/exhaust volume. These heads mandate a 4.230-inch bore.


When you compare the Bear Block Motors castings to original Ford, they aren't in the same league because casting technology has changed significantly in 50 years. Here are examples of original 427 castings.

11. Steel cylinder sleeves are siamesed for extraordinary strength and stability.

12. Head on, it’s tricky to tell the Bear 427 from an original with the exception being high casting and machining quality.

13. Indestructible 8620 steel main caps with studs and alignment pins yield stability like never before.

14. Throw a coat of paint on this and it’s virtually identical to the original side oiler 427 block.

15. The Bear Block Motors FE cylinder head is available in “as cast” and optional CNC ported. This high-quality casting is engineered for high-performance use and, as such, has been well thought out in every respect. We’re talking the more common 11⁄32-inch valve stem, 2.150/1.680-inch standard valve sizing (2.250/1.780-inch optional), high-swirl 72cc chambers with excellent quench to where you can run these guys on pump gas. Exhaust bolt patterns accommodate Ford compacts and intermediates as well as fullsize.

16. Check out these high-swirl 72cc chambers, which are the result of years of development to achieve the most optimum power-making FE chamber. Good valve shrouding. Large 2.150/1.680-inch stopcocks are standard. CNC porting optional.

17. Look at the evolution of Bear Block Motors cylinder heads through development. The GEN 1 head was a more traditional FE shovel chamber. With a lot of engineering time invested, the shovel chamber evolved more into the GEN 6 high-swirl chamber that made the final cut. A lot of time and thought have gone into the development of these heads

18. Here’s a 427 casting from the mid-1960s. Talk about a rough sand casting? Some 427 castings had these ribs while others did not. Cross-bolt caps required spacers.

19. Here’s an original 427 side oiler casting, easily identified by the side oil galleys and plugs.

20. Not all original 427 blocks were drilled for hydraulic lifters. This block isn’t.

Additional Sources:

Blue Oval Performance Engineering
(303) 762-8298