I don't think there's an issue in removing it. And IMO if you're trying to do a performance engine you may want to shave some weight off the flywheel and rebalance it to the new engine/crank assembly so it revs faster (shaving extra weight off the rods helps this too).
I would like to see the info on this too. I'm wondering why you chose a 4.5 block vs a 5.0 block since the iron is so much heavier. I personally would love a neat project like this, but I'd probably use a 4.2 block since it's the lightest and try to bore/stroke that
