My recommendation would be to leave the original blocks alone for two reasons: 1. it's a clone; and 2. the new GM ZL-1 casting is close in appearance and stronger.
New GM ZL-1 Block
If you are going to use the car at all, this is probably a safer route to go. COPO Pete is using the new casting in his factory stock COPO Camaro to great effect (11s in the 1/4). He built his motor up with NOS 074s and other NOS or excellent quality original parts. He was limited by factory stock considerations, that you may not so you could have more flexibility on updated internals.
I was going down this route before I bought my original.