The Dyno
With our 440 re-assembled, it was time to quantify the value of our mods on the dyno. We intended to start with the ported Indy 2D two-plane intake manifold, topping the engine with the same Demon 850 carb we had run in the previous test session. Unfortunately, our 2-inch Hooker SuperComp headers were not available to us on test day, but we did have a set of tti 2-2 1/8-inch step headers at Westech's dyno facility. We had tested these two headers back-to-back in a previous test, and found the results very close on a 650hp, 452-cube RB. Upon firing and warming up the engine, we detected a problem in the ignition system, which was traced to the magnetic pick-up in the distributor contacting the reluctor in the Mopar distributor. With the distributor damaged, we made an expedient change to a MSD distributor, which also required changing the right side valvecover for clearance. We would not expect the distributor change to have an effect on output.

With the bugs worked out, it was time for some power runs. The engine was run at a static pull to access the air/fuel ratio, and the jetting was adjusted as required. Satisfied with the jetting, we moved on to a timing loop and, surprisingly, found best power at an indicated 39-degrees of advance. How much power? Pulling the engine from 2,500-6,700 rpm, peak horsepower came in at 632 hp at 6,300 rpm, a gain of 72 hp over the best observed with this induction combination in the previous test session. The solid roller did exactly what it is supposed to do, applying controlled motion to the valvetrain, extending the power curve by allowing the engine to continue making power higher in the rpm range. While the power gain was remarkable, torque was remarkably broad, topping the 500-lb-ft mark at just under 3,000 rpm, reaching a peak of 565 lb-ft at 5,300 rpm, and remaining above 500 lb-ft through 6,500 rpm. Torque, torque, and more torque everywhere on the curve. We were impressed.

Looking to edge up the peak power figure still further, we installed a Wilson 1-inch tapered spacer under the carb. Typically, a spacer will help a dual-plane intake in the upper reaches of the rpm range, at the expense of some torque at the bottom end. The object is to try it and see if the trade is worthwhile. The tapered spacer showed its merit at the top, edging power up to 640 hp, at the same 6,300-rpm peak. Interestingly though, torque very low in the rpm range was indeed sacrificed, but by 2,800 rpm the loss was recovered. In practical terms, loss that far down in the rpm range probably wouldn't be missed, since even a mild 11-inch torque converter will put the engine above that rpm range right off the line. A spacer makes sense, if hood clearance will allow running one.

We were very satisfied with the results shown by the 2D Indy intake, and in the operation of the Comp Street Roller camshaft. The engine idled at over 12-inches of vacuum, despite the more radical cam specs, and the airflow numbers showed cam/valvetrain combo stable at 6,800 rpm, the highest rpm level the engine was run to. While 640 hp was a very satisfactory peak, we still had the Indy single-plane manifold to try. The Indy intake is a race-style high-rise single-plane, with a runner and plenum design that is very well suited to high-rpm output. We expected to see an increase at the top end with this intake. True to form, the single plane unlocked a healthy amount of hidden power up top, raising the bar to 655 hp at the same 6,300 rpm peak as the two-plane, for a 15hp advantage, peak-to-peak.

Looking at the torque curve showed that the single-plane actually unleashed more peak torque than the dual-plane, topping 578 lb-ft. The single-plane showed a solid gain in both the torque and horsepower peaks, but that's not the whole story. From 2,500-4,300 rpm, the dual-plane produced more torque. At 2,800 rpm, the dual-plane held an advantage of over 50 lb-ft. By 4,300 rpm, the single plane caught up, and kept going for a higher peak number, and kept the edge. Interestingly, rather than dropping off, the torque curve generated by the two-plane tracked virtually identically up to the top of the rpm range with the single plane, just a little behind in torque production. The gap actually narrowed towards the very top of our test.

The Mauler 440, at 655 hp, is making quite a bit more power than we originally intended from this build, due in large part to the awesome power potential of the CNC Indy cylinder heads. Torque, at 578 lb-ft, is a little short of our admittedly ambitious original target of 600, but the curve is much broader than we expected. Part of that is the result of the somewhat wide 112-degree lobe separation angle, which will typically shave some of the peak torque and broaden the torque curve.

What's next? We really should drop this monster in a car, but we are toying with further modifications to see what other fun we might have with a basic 440.