At PHR's annual engine-building shootout, the AMSOIL Engine Masters Challenge, many of the competitors fall into one of two camps. There are the guys whose engine platform of choice is the one that they feel best stacks the edicts of the rulebook in their favor. Let's call them the pragmatists. Since making horsepower is all about optimizing airflow, it's not surprising that the engine platforms with the broadest selection of potent induction components are often the most popular. At the other end of the spectrum, there are guys who will build their favorite engine platform of choice no matter what, rules be damned. Let's call them the passionate loyalists. From Cammer Fords and Pontiacs, to AMCs and Buicks, thank goodness for the men who love these motors, because they're the ones who add a big wallop of intrigue and spice to the competition.
Big displacement is the big-block Ford’s specialty. Thanks to a commodious crankcase, a pr
Todd Miller of TM Enterprises is a Ford Boss 429 fanatic, and for him the choice was between building a Boss motor or building nothing. He loves the Boss platform so much that he personally developed an all-new hemi cylinder head casting that bolts up to any Ford 385-series big-block. We say personally because Miller's a foundry mold and pattern maker by trade, not an engine builder, and he painstakingly dedicated his free time to designing a set of brand-new cylinder heads for the Boss faithful. Not only does the AMSOIL Engine Masters Challenge provide a great excuse to show off his new Boss head, but the lessons learned from competition also serve as a great opportunity to further refine and develop the TME product line.
Seriously Big Boy
Among the 31 engines that competed in the 2012 AMSOIL Engine Masters Challenge, TME's Shotgun Ford was the largest at 545 ci. In fact, most of the top finishers in the Street Division fielded motors that measured 100-150ci smaller, which is no coincidence. While the EMC scoring system divides the horsepower and torque averages of an engine by its cubic inch total to neutralize the benefits of larger displacement, all Street Division engines must exhale through a pair of 3-inch Flowmaster mufflers. This presents a substantial handicap for larger engine combinations, but Miller didn't care. "A 545 is way too big of a motor for the small exhaust you have to run, but this short-block is basically a test mule for our parts development, which means it has to be representative of what one of our customers would build for a street car. A small-bore, long-stroke motor with half the intake port volume filled in would be a better setup to score a lot of points with, but this engine isn't a dyno queen or a ringer by any means," Miller explains. "Given the tremendous airflow capabilities of the Boss cylinder heads, in a street application there's no reason to bolt them to a small motor. These Boss motors love lots of cubic inches. Since it doesn't cost any more to build a bigger motor and you have the cylinder heads to feed it, you might as well put a long-arm crank in it and let it eat."
In addition to long cylinder sleeves, tall-deck blocks offer thick piston compression heig
A closer examination of the Ford 385-series big-block architecture reveals why Miller decided to defy convention and go big. Simply put, big-block Fords are easy to build big, but it's hard to make them small. With a 4.900-inch bore spacing and a 4.360-inch bore, a factory 460 Ford dwarfs the 4.840-inch bore spacing and 4.250-inch bore of a 454 Chevy. Furthermore, while the 4.390-inch bore dimensions Miller settled upon might seem somewhat large, Blue Oval boys routinely open them up to 4.440 inches and larger. When it comes to deck height, the 385-series block stands tall at 10.322 inches with a cam tunnel pushed way up high in the block. This allowed Miller to drop in a 4.500-inch Scat forged crankshaft without having to grind down the rods or crankcase for clearance. He matched them up with a set of Scat H-beam 6.800-inch steel rods and Diamond 10.5:1 pistons. In contrast, a 9.800-inch deck factory 454 Chevy block typically requires a fair amount of grinding with a 4.250-inch stroke. In other words, big-block Fords beg for big cubic inches, and it's no wonder that hot rodders often build them as large as 557 ci.
Practicality notwithstanding, the TME 545 more than held its own for a combination that wasn't optimized for the EMC competition, finishing 12th out of 20 entries in the Street Division. Much of that success is attributable to the combined brainpower of Miller and his partner in crime, Eric Simone of Shotgun Hemi Parts. Simone has done just about everything in a distinguished career that includes engine development work for Ford Racing, Roush-Fenway Racing's NASCAR program, IHRA Pro Stock, and NMRA Outlaw 10.5. Likewise, he has entered several of his own motors in past EMC competitions. In an effort to boost low and midrange torque, Miller and Simone spec'd out an under-square short-block that combines a 4.390-inch bore and a 4.500-inch stroke. Likewise, the COMP hydraulic roller cam provides .799-inch lift, but duration was limited to a conservative 248 degrees at .050. A tight 108-degree lobe separation angle shifts the power curve to the low and midrange as well. "The idea with the cam was to pick the valves up into the fat part of the lift curve where the heads move a lot of air, but then keep the duration relatively short to increase low and midrange output," Simone explains.
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.
|BY THE NUMBERS
545ci Ford Big-Block Hemi
||COMP Cams solid roller
||248/248 degrees at .050-inch tappet rise
||T&D 1.75:1 ratio
||Total Seal; 1/16, 1/16, 3/16
||Factory Ford 429/460
||Scat 6.800-inch H-beam
||TM Enterprises Boss 429 castings
|Intake valve diameter:
|Exhaust valve diameter:
||C&C Motorsports single-plane
||FAST 2,000-cfm four-barrel
||Hedman 2.125-inch primary
||Dual MSD 6AL-2
The square intake ports on TME’s prototype Boss heads are a stark departure from the stand
Custom sheetmetal intake manifolds cost big bucks, so with some forward thinking, Miller d
The stock Boss valvetrain will bolt right up to the TME heads, but Miller opted to upgrade
|ON THE DYNO
|545ci Ford Big-Block Hemi
In an effort to reduce the plenum volume of the intake manifold, the floor was filled 1/4-
The TME 545 boasts a unique dual spark plug design that’s fed off a pair of MSD distributo
To boost low and midrange engine output, the camshaft was ground on a 108-degree lobe-sepa