Yes, 6-pack rods. Correct balancer.

So..how do I tell heavy rod flywheel?

A buddy just pulled apart a heavy rod 72-440 that was in his roadrunner and I was thinking of borrowing his. But he tossed the harmonic balancer (duh!!) as he thought it was shot. I wanted to look at it to see if all his parts matched properly before hand. (PS, non-mopar guy, so nice lesson for him.) Engine definitely had heavy rods, though.