So I've got a 4.1 Buick V6 in my 1980 Chevrolet Monza that the previous owner was intending on building, however I plan on going a different route with the build and swapping in a 5.3 LM7. The casting number on the block is 25506484. The problem is that I am unable to find any 4.1's for sale to base my asking price off of. If anyone knows what these engines are worth, please let me know. The engine is totally stock to my knowledge aside from a Smokey Yunick Weiand 7542 intake manifold.