Major upgrades! Any ideas on hp gains?

Well my mind has gotten the better of me, or maybe experiance is setting me strait here.
I have decided to hold off, putting the heads on. Reason being, I think I was misled. I know they are 72 360 J heads, I ran the numbers and they have an obvious "J" on them. But were I think I was BS'ed was, he told me that they were a fresh rebuild. This was about 8 years ago (my car has been sitting while I collected parts while in the Navy). Well I bought them thinking they would just be slapped on and go! Upon further inspection over the last several days I noticed there was some glass beads holding a valve open (it has been sitting on the valve seat for bout 8 years now, aswell as Im not sure where esle the beads may have found a home. Also I see there is a decent amount of carbon in one or two of the really hard to get areas in the valve chambers. All this leads me to believe that I have been played! I am sure you all get the same impression! I think they were old and were bead blasted to be sold as new.
So like I said I think my experiance is getting the best of me because I decided to get them checked out before I put them on.
Aside from that I dont have the correct intake for that combo right now and Id rather do it all at once, so Ill wait to get the intake and then just do a top end swap!

Plus I have to say I like the torque that it has at the moment! Thx guys talk to ya lata'