The GMC V6 websites engine data page lists the power in both gross and net power. So you have the "old" and "new-modern" power numbers
I have seen a GMC 379 V6 dumped up to an 8.6:1 compression ratio lay down 175hp@3,400rpm / 388tq@1,600rpm on a dyno print out.
I myself have thought about combining the 4.25" bore of the 305s with the 3.86" stroke of the 379/478s and having a small but torquey GMC V6. Say 328-ish cubes ?
Mike