These cylinder heads were on a 302 I purchased a while back. They're ported by Slover's Porting of Sun Valley, Cali. I've looked everywhere for reviews of their work but can only turn up recommendations and reviews from import cars. AFR list them as a porting service so I would have to imagine they're good at what they do. Their website shows a lot of work they've done for salt flat racers too. Does anyone have any info/experience with these guys? I've had no luck at contacting them electronically, next is to try an call them and hopefully I can get specs from them if they kept em from the 70's. Only thing to worry about after all of that is if the things are crack free.