429 pushrod Help

I recently bought a 78 Ford F150 that some started but did not finish. I rebuilt the 429 that was in the truck when I got it. Well I bent 8 of the 16 push rods after running it for the first time. The push rods are 8.648 in length, with non adjustable rocker arms. They are DOVE Heads and D1VE Block. My question is should I be using a shorter push rod? I found they also used a 8.690 length in the early seventies, and a 8.550 length after 1973. The cam is slightly over stock.

Thanks