Honestly, that is not bad for 11.55 compression and 3720 lbs. (505 HP)
Since you mentioned "improvement with minimal investment", I'd start
looking for places to take out weight. That's about as cheap as you
can get.......and effective.

Everything else looks pretty decent together. Maybe another 1.5 point
compression with another 10º cam, an 8' converter in a 2.74 low gear
904. Nothing really as cost effective as whittling down the weight.

After I got as much weight out of it, as I could, then I'd swap to a 2.74
904 with a matching 8" converter. Only then would I start messing with
the engine. The weight alone (200 lbs.) should get you 7.0s.

Good luck.