'69 rods, or thicker '73 ones?

Its not a bad idea to upgrade to the heavier rods, but for street use, the lighter rods are okay too. Compare the stock lighter rods to ford 302 or chevy 350 rods. They are beefier. There are several things to remember - you'll need to re-balance the rotating assembly with the heavier rods, and you will be going from a floating wrist pin to a pressed pin. I built my latest 318 with the lighter rods, mainly because it had already been overhauled when I got it and I was doing a freshening.

Cheers !