Sneaking in under the radar...
Sneaking in under the radar is this modified HVH super sucker carb spacer. Brett milled off the bottom of it and re-drilled the intake to bolt it directly on with just a thin layer of sealant.
For the cylinder heads, Miller knew that he had to make the right choice or risk losing out on big torque and/or horsepower. All of his experience and research led him directly to Indy Cylinder Heads. Their line of big oval-port heads was where he started. Indy offers their castings in a few different configurations and Brett preferred the earlier style CNC-ported combustion chamber design along with their latest 230cc CNC runner design. Some numbers were keyed into the machine and a few hours later, Brett's heads were spit out of the CNC mill and ready for delivery. They would be perfect as-is for a higher-rpm engine, but as he was shooting for big average torque and horsepower numbers across a broad range, he wanted them just a little smaller. "It was a 360 CNC runner that started out at 230 cc, and we shrunk them down to 210." Compared to the stock 2.02-/1.60-inch valves in the original 340 heads, the massive 2.10/1.60 heads had no problem moving the air. To control the valves as they were pounded open and shut, a set of COMP Beehive valvesprings was set up right at 150 pounds on the seat and 420 pounds open. "I don't think I could have put enough spring force on it for as fast as I was trying to open those valves with that [T&D] 1.8 rocker and that [COMP] MM lobe. There's just a ton of weight in the valvetrain."
Edelbrock just about has the market cornered on intake manifolds, and that was what was on the 345. The Victor W2 Miller chose is actually such a nicely designed intake that many of the Chevy guys have adapted for use on their small-blocks. Brett massaged the big oval runners to match the heads for an easy transition and lots of velocity. The benefit of the oval design is the ability to get the maximum amount of air down the pipe without having dead spots like a conventional rectangle port would have. Eliminating the dead spots while keeping that air going gets the ports really working faster, increases the signal to the carb, and starts building torque sooner. Perfect for a fun street/strip engine destined to blow off the tires at will. More modifications converted the 4150-style intake to run a Dominator carb. As the Challenge rules only allowed use of a 1.5-inch carb spacer/adapter, Brett milled off the bottom of a taller HVH adapter and recessed it directly into the plenum. Pretty sneaky.
Under the Super Sucker lies...
Under the Super Sucker lies the W2 plenum with extra-long runner extensions fooling the ports into thinking they are longer than they are, and making more torque.
Long oval runners maximize...
Long oval runners maximize the area in the center of the port and eliminate any dead zones. That design was certainly a key reason for the small Mopar to make as much torque as it did, even with a single-plane intake.
Even with a fairly long 6.125-inch...
Even with a fairly long 6.125-inch rod, the piston had tall compression height. Regardless of any Internet jabber about rod-to-stroke ratio, in reality, there is little proof one way or the other that the rod does little more than connect the piston to the crank. In some cases, a long rod might act as a crutch for poor cylinder heads, but in this case the 1.85 ratio is a factory design that doesn't seem to need any improvement.
Tight, well-designed combustion...
Tight, well-designed combustion chambers and a 0.040-inch quench made the burn efficient, and the dyno responded by indicating the engine only wanted 33 degrees of total timing.
Using epoxy, Miller filled...
Using epoxy, Miller filled the floor of the runners, as well as some of the bowl area. Testing on Vic Bloomer's flow bench showed no loss in flow numbers, and the results once again helped build power early on in the dyno pull.
Beehive springs were thought...
Beehive springs were thought to be a little "out there" not too long ago, but they are showing up in more and more high-powered engines, and with good results. These COMPs were able to provide great control without wasting effort by rubbing against an inner spring. Stability was also helped out by the heavy-duty ?-inch pushrods.