Due to their unique valve positioning, Ford Hemi heads require different pistons than a st
In an effort to swing the pendulum back in the direction of street performance, the rules for the 2010 EMC sought to ban hardware rarely seen on the typical street machine. The 2009 competition had seen an influx of tunnel-rams and dual-quad carbs, so in 2010, carbureted motors were limited to a dual-plane intake and a single four-barrel carb. Although EFI motors were allowed to use any commercially available fuel-injected manifoldas long as it had a single throttle-body and cast-in injector bungsall engines had to run hydraulic roller cams limited to a maximum of .650-inch valve lift. Given these restrictions, TME’s Boss combines an interesting mix of components that set it apart from the typical EMC motor. At 477 ci, it’s a giant in relation to the rest of the contestants. In fact, of the 38 entrants, only four fielded motors with more cubic inches than TME’s 477. Since the EMC scoring system averages horsepower and torque from 2,500 to 6,500 rpm, then divides those totals by an engine’s displacement, having more cubic inches doesn’t always pay off. As such, more than half of the EMC field (24) was comprised of small-blocks, something that can’t be chalked up to mere coincidence. Miller agrees: Since you have to run through a 3.5-inch exhaust system and are limited in valve lift, the rules naturally favor a smaller motor. All of the top finishers had motors that were right around 400 ci.
With enormous 9⁄16-inch ARP main studs, the factory two-bolt caps can easily handle 800-pl
Despite the dominance of smaller-displacement combinations, Miller’s reasoning for going big makes perfect sense. I don’t build engines full time, and for me it’s just a hobby gone wrong. I don’t have the resources to build a dyno prima donna motor, so I had to build an affordable combo that I could actually put in a car and have fun with on the street, he says. To keep costs down, Miller scored a plain-Jane production 460 block out of a salvage yard for $35. The displacement we ended up with was half by accident and half by economy. The Boss was originally designed as a high-rpm motor, so we knew we had to downsize it significantly to tailor the powerband for the EMC points system. While big-block Fords are easy to make big, they’re very hard to make small due to their large 4.360-inch bore. It was questionable as to whether or not the block was going to clean up at .030 inch, so the machine shop just bored it .080 over. The 4.440-inch bore was then matched up with a 3.850-inch crank out of a stock Ford truck motor, as we felt that was a better option than a shorter 3.590-inch stroke crank out of a 429. I’d love to build an under-square motor with a 4.250-inch bore and a 4.500-inch stroke to try to boost torque, but that would require sleeving the block, and I wasn’t interested in spending that kind of money.
Swinging on the Scat 6.535-inch big-block Chevy rods are Diamond 11.4:1 pistons. They have
Due to the limited selection of aftermarket big-block Ford connecting rods, Miller ground the truck crank’s rod journals down from 2.500 to 2.200 inches. This change allowed tapping into the massive catalog of big-block Chevy rod offerings, and Miller opted for a set of 6.535-inch H-beams from Scat. Although the 460 block’s generous 10.322-inch deck height has plenty of real estate for much longer rods, Miller felt that the increase in rod angularity of a short-rod combo would yield dividends in the low-end torque department. Rounding out the rotating assembly is a set of Diamond 11.4:1 pistons whose crowns perfectly follow the contours of the Hemi combustion chambers. When it came time to select a camshaft, Miller relied upon the expertise of COMP Cams. Given the lift limitations that were put into place in 2010, I thought the smart thing to do was to call up Billy Godbold at COMP and have him spec out a cam for us. He designed a 247/251-at-.050 hydraulic roller grind for us with .634 lift, and it ran best at 2 degrees advanced just like he said it would, Miller says.