Muskegon is a hard company to find out any information about but I'm fairly certain they were bought out by Crane back in the 70's. I was told by the person I bought these cams from that they were for small block Chevy but I haven't been able to verify that. I've had these for about ten years and it's time to let them go. They do have some surface rust that should buff off pretty easily. Contact me through Nextech or at 620-295-0793. $20 each or all for $50.