Quote: I was thinking some of the engine guys on here would have answered your good question by now. Cat got their fingers or writers block! So from the Village Idiot of Hemi:
The long rocker arm is on the exhaust side its not near the issue it would be if it was on the intake side. The exhaust rocker is aided in closing by the out going exhaust gasses. In a way, it has some help so the mass of the rocker on the exhaust side is not really an issue at all on the Hemi engines. It posses no problem what so ever to increasing the RPM range of the engine. Some Bob Glidden Pro Stock Ford Hemi engines turned well over 9500rpm with a similar length and far heavier weight rocker arm. We also have springs now days that handle much more than what we throw at them. The number one problem to increasing engine speed with a Super Stock Hemi is area. More precisely, valve area and port area. These engines are limited to a stock valve size and you can only fit so much air past a certain size valve.
That should bring them out!!!!!!
The reason I ask is because I'm a college student in the process of designing a cylinder head so I was trying to spec out the rocker position of the intake and exhaust. The design issue I'm facing is whether to leave the pushrod straight which means having a longer rocker arm or put the pushrod at 5 or 10 degrees and having a shorter pushrod which will create some side loading at the lifter. I know the pushrod is going to sideload some, but I'm curious of how much force is required to make side loading a major issue. For example, at 5 degrees with 2000lbs of force down the pushrod will create a side loading force of 174lbs or with 10 degrees, 348lbs of side load force. I cant do much with to fix the Intake pushrod angles due to how big I'm trying to make the Intake ports and the crappy positioning lifter bores in big block chryslers. Anyway, with this design, I want and need the valvetrain to be able to spin up to 11,000rpm without causing such significant wear that the design is useless. I appreciate the help and I will also consult some other individuals as well.
