If you bought a roller block used for like $400, and had it machined and bored and new pistons, etc - you'd have a forty over block and at least $2k in it, especially if you re-used those heads and had them re-done. So you did very fine on this at $2k.
I think I'd leave the heads on, but put on a new water pump and thermo-stat, looks like you may swap cams so that is a good time for that stuff anyway.