Hi im going to buy some of your engine paint for my 56 plymouth, and was wondering if I can add metal flake to it? I was thinking that I could buy the engine paint and take it down to a local paint shop and have them mix in some metal flake to add a little bit of a custom look to the paint. Would this work, will the paint mix well with it and still adhere to the motor? Im wanting to keep the factory paint color with some speckles in it. Any suggestions and advise would be appreciated thankyou!!!