Welcome aboard Komisarz,

Since you're new here and don't know my twisted sense of humor I'll resist saying, "just flip the gaskets over!"

As the Cleveland isn't stock to a '67 I would suggest you run the engine serial number for authentication of the year and model of the engine. Given that, a decent parts guy should be able to figure the correct application. An alternative would be to get the casting numbers from the heads and have those run. Let us know if that works for you.

Here's a link to a site that explains the variants available in the Cleveland and M blocks as well as what's interchangeable. Based on what it says, there shouldn't be a problem. http://home.earthlink.net/~bubbaf250...history03.html