Engine Design Service

Hi everyone.  I am wondering if anyone knows of an engine design service.  I don’t know if there is even such a service available.  What I am looking for is a someone that will evaluate the parts that I have, run the air flow information through an engine modeling program to tell me if there may be any potential problems.  I do realize that there are engine modeling programs and information banks available on line but I am not familiar with them.  I would prefer to have a professional do the calculations and give me their recommendations.  Any advice will be greatly appreciated.  Thanks jimzilla.