On the B/E body the rack sits (rearward) closer to the steering knuckle ends, so if you want to remove some of the spacer, the effect is minimal. You will need to leave about 1/4" for rack clearance. Just test by stacking a couple of the big thick washers. That should help the #3 tube
For the #5 tube......on the A body Hemi builds, for additional clearance, I cheat the steering shaft as far left (drivers side) as possible, often slotting the firewall bracket slightly to get all I can get. A small amount at the firewall yields quite a bit at the shaft end.
You can see now why the Hemi sits where it does.....your mod for the Stage V heads is probably the best way to go.....not much room to move the motor more to the left.
It is a dance to find the perfect location.
Lastly....I would ADVISE to not dent anything until you get the actual block in there. I have read of too many issues from relying on the plastic blocks for critical clearances.