We conferred with Bob Woods of The Supercharger Store, and he agrees, in fact pointing out that the larger blower kits he normally sells always come with a cogged drive. Chalk one up for experience, we blew it when ordering our setup, and then opting for the larger blower later. We placed an order for the cogged drive, and in a few days were ready for another crack at the dyno. The pulley system directly replaced the serpentine setup, bolting on in minutes, and once again the 440 was ready to run. The cogged drive eliminates all potential for slip, reduces the tension required, and is just plain bulletproof.
Back at Westech, the 440 was again mounted to the dyno, and this time we were ready to let it run for the numbers. The potential had already been shown in our last test session, with over 750 hp on the dial. With the cogged belt drive offering the promise of being able to make full high-rpm pulls without slippage, we knew the 440 would deliver. Deliver it did. We wound the engine up to 6,400 rpm, and the boost just kept coming. A peak output of 878 hp at 6,300 rpm is pretty hard to argue with, especially considering the basic package below. We made several pulls that day, and the power number and boost level repeated like clockwork, run after run. Dialing in more timing than the 25 degrees we started with didn't show an improvement, so that's where we ended up. The Flatout head spacers sealed like a vault, and the 440 showed no signs of distress. For an engine this size, 878 hp is an all-out racing engine's output, but the engine ran just as docile at idle as before--in fact, even more so given the wider lobe separation and reduced overlap. EM
Carb vs. InjectionWe were impressed with the amount of pure horsepower out 440 Mopar made with the blow-through carb arrangement, but the reality is that it took some doing. Initially we had a dedicated "blower carb" bolted to our engine, and the fact is it didn't want to run under boost, no matter what we did at the jet. The carb simply would not provide a working fuel curve, actually delivering less fuel as the boost escalated. We had direct readings of air/fuel ratio and fuel flow, allowing us test through and identify the problems without destroying our engine. We pity the guy who bolts a problem like that on and tries to tune it in a high-powered vehicle. We solved the problem by bolting on another carb, and tuning from there. At best the mixture curve was a compromise, but it was a working one. Generally, you are going to be pig-fat down low to get enough fuel to avoid a lean condition as the boost builds.
Frankly, a carb is a velocity-sensing device, and that is the key variable upon which a carb varies the air/fuel ratio. It does a very poor job of compensation for changes in pressure. That's the plain physics of how it works, period. It will work best at lower changes in pressure, which means lower boost. Outside of that, it will be difficult or impossible to tune the carb to offer an optimal air fuel ratio over a very broad rpm range, with the accompanying broad pressure changes associated with rapidly escalating boost pressure. For a high-powered, high boost engine expected to operate efficiently over a very broad rpm range, I would highly recommend an EFI system.