Custom implementation of the solr DefaultSimilarity class. With this no internal solr score changes will happen.

MyNewSimilarityClass.java

package org.apache.lucene.search.similarities;

import org.apache.lucene.index.FieldInvertState;
import org.apache.lucene.search.similarities.DefaultSimilarity;

public class MyNewSimilarityClass extends DefaultSimilarity {

	@Override
	public float coord(int overlap, int maxOverlap) {
		return 1.0f;
	}

	@Override
	public float idf(long docFreq, long numDocs) {
		return 1.0f;
	}

	@Override
	public float lengthNorm(FieldInvertState arg0) {
		return 1.0f;
	}

	@Override
	public float tf(float freq) {
		return 1.0f;
	}

}