I have a 454 slightly bored over, making roughly 450/ 550 hp & Tq.

It is in a 1970 Nova, with power steering - I have been told by mechanic dropping in this engine that no header will fit and that 1 7/8" headers are big enough.

Are there any suggestions for the correct size header primary and collector?

thanks
(dropping in this engine has turned into the biggest hassle ever, any help is so greatly appreciated)