Well, they know what they can or will do, and what they won't.

If it was just annealing, one heats the end to full red heat and let air cool.

But., by the time they cut to length, either pull pushrod ends or supply new ones, ream the hole to fit the new ends, they've got enough time ($$$) into the pushrod that it makes sense just to buy a new set the right length.

If you're doing it yourself and your time is worth nothing, then shortening could make good sense.

Another route is http://www.oepushrods.com/, thanks to MrP for the tip.

R.