The extreme pushrod angularity created by the hemi architecture requires running Crane lif
To understand what would drive a man to dedicate years of his spare time designing an all-new Ford hemi cylinder head requires understanding the mystique of the fabled Boss engine program. In an effort to chase down the dominant Chrysler Hemis in NASCAR, Ford unveiled the super-trick 427 Cammer in response. Unfortunately, NASCAR banned the Cammer from competition in 1965, which prompted Ford engineers to whip up their own pushrod hemi cylinder heads. Upon bolting these heads to a fortified 385-series short-block, the Boss 429 was born. It promptly mopped up at the '69 Daytona 500 and remained dominant throughout the 1970 season until Ford execs decided the Boss program was too expensive and pulled the plug. NASCAR homologation rules required selling just 500 Boss motors in street cars during each of those two seasons, so the number of original Boss cylinder heads still in existence is extremely scarce. Those that have survived are often in poor shape and command staggering price premiums.
These factors set the stage for Miller to design his own Boss cylinder heads, which are distributed exclusively through Shotgun Hemi Parts (www.ShotgunHemiParts.com). To ensure compatibility with plain-Jane 385-series short-blocks, the first order of business was eliminating the quirks of the factory Boss heads. Unlike the factory heads that relied on clumsy O-rings to seal the cylinders and water passages, the TME heads use a modified version of a standard Fel-Pro gasket. TME also reinforced the bolt support columns to allow for much greater fastener torque values, clamping force, and casting stability than the factory Boss heads. To further enhance durability, TME subjects its heads to a modern T6 heat-treating process as well. The only other modifications required to bolt a set of TME heads to a standard big-block Ford are routing a pair of external oil drain-backs to the oil pan, and slightly notching the deck surface of the block for pushrod clearance.
TM Enterprises offers its Boss heads in two configurations. Its entry-level head features
For the 2012 AMSOIL Engine Masters Challenge, Miller busted out the third generation of this Boss cylinder head. TME's standard Boss heads feature CNC-machined ports in the factory locations to maintain compatibility with factory intake and exhaust manifolds. Even so, they flow a stout 440 cfm, and have already proven themselves in past EMC competitions. For the 2012 contest, TME went back to the drawing board with an all-new, raised-runner design. "The valve angles with these new heads are still in the factory location, but the intake ports have been raised nearly ⅞ inch. This decreases the angle of the short-turn radius, gives the air a much straighter shot to the intake valve, and reduces air/fuel separation," Miller explains. "Right out of the CNC machine, the intake ports flow 480 cfm. These aren't the kind of ports you'd normally take to EMC, but most of our customers aren't going to fill in the port floors so we didn't, either. As it sits, this is a prototype port design, and we're looking to squeeze some more flow out of it in the near future."
Fancy cylinder heads often require custom one-off intake manifolds and supporting hardware, but TME wanted to maintain compatibility with existing off-the-shelf parts. As such, TME's new high-port heads mate up perfectly with cast single-plane manifolds offered by C&C Motorsports. For his 545, Miller filled the plenum floor ¼ inch with epoxy in an attempt to boost air velocity. The intake has been modified for a set of 65-lb/hr fuel injectors, and is fed by a FAST 2,000-cfm four-barrel throttle-body. Managing the fuel and spark control is a FAST XFI fuel-injection system along with an MSD ignition.
Big Horsepower Corked, Bigger Horsepower Uncorked
With a traditional wedge head, since the intake and exhaust valve sit side-by-side, maximu
Despite the concessions made to ensure that the TME 545 Ford was built more like a customer's motor than a combination optimized for EMC, the Boss kicked out 751 hp at 6,200 rpm and 704 lb-ft of torque at 4,800 rpm. The original Boss 429 earned a reputation for peaky high-rpm performance, but when modern cylinder head technology gets combined with proven hemi architecture and 545 ci, the result is 605 lb-ft at just 2,700 rpm. Mind you, all of this is through a set of 3-inch mufflers.
Naturally, figures like that make you wonder how much a combo like this would put out in uncorked trim. "Before packing up the motor for EMC, we ran this exact same engine combo through 4-inch collectors and an open exhaust on a local dyno, and it made 880 hp at 6,500 rpm. We're looking into revising the combustion chamber design, so there's probably even more power left in the package," Miller says. Nevertheless, rules are rules, everyone in the Street Division had to run their engines through the same 3-inch mufflers, and a 12th Place finish is a 12th Place finish. Even so, Miller's infatuation and dedication to the Boss platform means that big-block Ford enthusiasts now have a devastating new weapon at their disposal that looks a lot like the original Boss 429 head.