I would like to make a few comments based on Madman's thoughts and use his truck as reference.
First off, I totally agree with Madman that items for these trucks can be deemed necessary when they aren't. Many of the products I designed were meant for a certain requirement (high rpm, fuel economy, etc. etc.) then someone will comment that said product helped in some way. Next thing you know many people are saying its a good idea or a requirement, even though I never designed the product to help in the area they are recommending. Make sense?
As far as Madman's stance on pushrods, my first question is, what section are we in? 6.4 Aftermarket. This is a performance section. Not for the stock guys. The guys in this section are looking for performance upgrades, if that be to the headlights or the engine or trans.
A heavy duty pushrod can and will deliver performance gains. Horsepower and Torque. Is it required, if performance is your goal, then yes they are required. Madman's truck is a perfect example, the funny thing is his truck would benefit from pushrods more than Beans. Let me give you why I say this.
I know I have talked about this before but I don't remember to what detail. I have been involved in quite a few engine programs that ran under certain restrictions. These restrictions were to even the playing field, to keep the budget under control. Sometimes the horsepower difference from the leader to the loser may have been 15hp or less. We spent days searching for a couple of horsepower. I know that in the diesel world right now with tuners that add 300hp, that a 2hp gain isn't important but it all adds up.
We had an engine that was running mid pack and could not run with the leader. We had maximized just about everything we could. Then we decided to run a larger pushrod. Just changing the pushrods gained us 20hp. That's huge! Sure on a chassis dyno and compared to a 310 tune there is no comparison but with performance as your goal, I will always take extra power.
Now why did we gain horsepower with a pushrod change. Easy, deflection of the pushrod. The valve lift is determined by the camshaft. Power is determined by how high and how long, and when the valves are opened. With the pushrods deflecting we lost lift and duration of valve opening and thus we had left power on the table. Once we went to pushrods that deflected less then our power came up.
Let's apply this to the argument at hand. We have an engine that has been tweaked to deliver 300-400hp more horsepower than designed. The exhaust pressures are substantially higher. That means the exhaust pushrods now have to try and open the valves under a much greater restriction of high backpressure than originally designed to do. The lifter starts to move and the pushrods try to open the valves. The valves don't want to open due to high bp and so the pushrod starts to deflect. Eventually the deflecting pushrod overcomes the requirement to open the valves and now the valves open and exhaust flows. Unfortunately it took 5 degrees of camshaft duration and .030" of valve lift before this occured. That sucks! We no longer have the exhaust flow that the truck was designed for. Power was left on the table.
Now we add valvesprings to combat the high bp the motor sees. The pushrods was already in a limited capacity and now we are asking it to open the valve with even more added pressure. What's it going to do? Deflect even more. So effectively our camshaft keeps getting smaller and thus airflow keeps decreasing.
Now we add our larger cam (This is Madmans motor). The cam lifts the valves even higher and holds them open even longer. The higher lift brings the valvesprings into a higher pressure. So not only are our stock pushrods fighting more backpressure than they were designed for, they are fighting more spring pressure than they were designed for, and by adding the cam we have now asked them to combat a valvespring at even higher pressure. Can they do it? NO. What happens is they deflect even more.
All that work to add the camshaft, but without a proper pushrod our valve lift, valve timing, and valve opening duration are not what the cam was designed to do. We are not getting what we paid for, the cam cannot deliver because we have skimped on required components.
So are Pushrods needed? Depends on your goal. If the goal is performance, yes! Madmans goal is performance, that's why he has an RCD cam, but he left power on the table by skimping on pushrods. Will he feel the power gain if he changes them, most likely not. Will his engine run fine, sure. But on an engine dyno you would see the gain. I know this because I have witnessed it many times. Do you want to run mid pack? Or do you want to be the leader?
Madman (sorry don't know your real name), I am not attacking you but you have opened your comments to criticism.
