These were old school Brodix heads cast for EPD when they were in business. I ended up with them on a motor I bought but really don’t have the knowledge or the application to use them. They are EB 510 series standard 4.84 bore space heads that were o-ringed. That’s about all I know about them. I was told they could be 500+ cfm heads and are believed to be 18* heads? Have a custom set of JE 4.5” bore pistons that match them too.