At the time Paul (who brought Christ to the gentiles) was teaching, some Jews said that the only way we could be included in God’s Kingdom was to not eat pork like they did. That made Paul angry. All along God was teaching to be clean and stay away from evil by eating only foods from animals who didn't eat refuse, and to be different from pagans. That was the main thing, what the not eating pork was for. Whether they did or not eat it wasn’t the important thing, but being clean was. Certainly gentiles could be in the kingdom and still eat pork.
Now your saying if any principles change God is not eternal? I don't read where in the OT they could eat pork. Why did it make Paul angry? Are you saying it is okay for a gentile to eat pork but not a Jew?
From your first post to this one, 360 degree turn in your view. God has given us the NT in which we are under, the OT testament is written for our learning, because we are not bound by it - Rom 15:4.
This does not make God one who changed, but one who had a temporary plan, looking forward unto the permanent covenant. In order for their to be a "reformation" their must be change.