I inherited these heads on a 428 wanna be 390 and I've never seen these modifications. What really throws me is the intrusion into the combustion chamber with steel plugs run through the lower exhaust manifold bolt holes. The heads resemble medium riser combustion chambers, have CJ intakes and Med riser exhaust valves. There is light porting and surfacing on both the cylinder side and exhaust manifold side. The heads have all new valves, springs, retainers, keepers , and guides. Someone has done lots of work here and I would like to get some opinions on whether these are useable or crap. Thanks for your opinions guys.
regards
Steve Legree