Is it the B block 347?
If so I had one years ago, I think mine was a hyper piston setup, not that it mattered the B block didn't turn out to be much if any stronger than a stock block.
Although that engine made a great NA setup, capable of 10's with the right heads, cam intake.
While if I was you i'd like to know too, since it's probably not built with an R block and you already know it's not a boss, it may not really matter what's in it, because you can't push it past 500rwhp anyway.