Dear Metal Bits,
I do not think HE30 would be the best choice. If I remember correctly, my machinist is using 2024. I think HE30 is 6083 maybe? The pushrod made of 7075 bent in the first race. It turned out that 2024 although lower in room temp tensile strength, kept a higher percentage of its strength at a higher the temp. Send me a PM if you want me to call him to verify. I have used both types of pushrods, namely, steel end and all aluminum. I do not think it makes much difference assuming you take the time to maximize the ball and cup contact area. This can be done with a stone or lapping in a drill press. The last pair I had made are all aluminum.
David