chevy parts are cheaper because so many different people that make them,everybody and their brother makes good chevy parts.With more sources to buy chevy parts from,the sources have to compete against each other and not only make better parts,but have to sell them at a cheaper price.
Us Mopar racers have only 2 sources if we want to build or buy Fast Hi-Powered engines.Indy or B1 their or enough of us Mopar racers that they don't even have to compete against each other.And most of the Mopar racers try to put either Indy or B1 out of business,and when other companies see this they are not even going to think about making any Mopar parts.