Correct, you will want your flywheel to be zero balanced, not balanced for a gas motor.That's awesome. Nice to see stuff come together like that.
If that is the flywheel off the V8, it might be balanced for the v8 crank. unlike the I6 flywheel.
So if you are getting it balanced don't get it balanced for a 304.
On the ring gear rub, Could be off in the centering, but it looks to me like the flywheel mounting face might be bit deeper than what the crank normally is, that or with not using the factory dust shield the flywheel is a bit deep in the bellhousing and that is what is causing the rub.