I don't think there is a member who think Edelbrock reinvented anything. Their head was sold as a direct replacement for a stock head, that'd be hard to do if you moved the rockers, changed exhaust & intake bolt pattern and port locations. They did make improvements though, smaller stem valves...
John, it's not so much about where it's made as it is about copying someone else's design. China made is a fact of life everywhere in the world today. If speedmaster was paying for a license to reproduce or a royalty, it would be a different story.
Would you be happy if someone took a set of...
This shouldn't be a surprise to anyone. Companies spend millions to develop and market a product, then someone like speedmaster has it copied in china with no developmental cost and sell it cheap. It's easier to make money when someone else has done the work and all you have to do is replicate it.
I'd take it to a test & tune, make some easy hits to get familiar with the staging process, where the stripe is and how the car is going to react. Once I had a good feeling for it, I'd make a full hard pass. If it's too fast and you get tossed ask the tech guy to look at the car and tell you...
No experience with M1 but several years ago I looked at a complete but apart 390ish inch W5 headed engine. It had a heavily welded W2 intake on it. When I asked why, the owner said his builder didn’t like any of the W5 intakes.
My Indy headed 434 has an Indy intake.