I Would have guessed it had a roller cam.
What we know:
-It's based on a 72 440 block and it looks like someone bought the Indy EZ -1 top end kit.
-EZ -1 heads use standard rocker gear. My GTS has stamdard rocker gear. Hmm...
Follow along as we explore the crusty, mud dauber filler caverns of this intruiging time capsule : D