Quote: If you're starting from scratch, buy a set of 6.4 apache heads. They come with a Ferea 5000 series valve factory and can accept a BBC valve spring like a PAC 1520.
$1220 with "core" charge and add in shipping.
Matt Deane in the parts department at Glendora Dodge has a set in stock. I know because I'm considering a set right now...350cfm OOTB with room to grow!