A shaft-mount rocker system’s job is to provide valvetrain stability in the upper-rpm range; however the added benefits can also result in a gain in horsepower by minimizing movement. While that may seem fairly obvious, we also learned that T&D Machine Products offers a variety of options to custom-fit any combination. Once we spelled out our goals, T&D recommended that we add the following options: First, the spring oil holes (PN 0720), measuring 0.040 inch and placed on the bottom side of the rocker. During the lift cycle, it’s constantly oiling the springs, helping to extend the spring life. The second option was the needle bearing tips (PN 0731); these feature 23 needle bearings in the roller tips and are recommended for high-lift applications and for endurance. Lastly, the steel rocker option (PN 0727); these are built out of billet chromoly, offering minimal fatigue with incredible strength in a lightweight construction. If you’re looking for a set for your mill, it’s definitely a good idea to call T&D directly.
If we had one issue, it was not having a large enough air-to-water cooler. Since our geardrive was spinning the Vortech V-28 123 at its maximum recommended rpm, we were expecting to see boost levels at around 35 psi. Only, this wasn’t the case, and we were seeing 25 psi at best. To locate the pressure drop, we placed boost sensors before and after the air-to-water cooler and found an 11-psi difference. Interestingly, we were averaging 30-40 hp per 1 psi of boost, which tells us there’s a good chance we can still gain anywhere from 330 to 440 hp with an appropriately sized cooler. We’re pretty pleased with the results for the time being, but you can bet we’ll get our hands on the bigger cooler and see if our theory stands true. CHP