Then casting #s really don't matter...LOL
Open or closed chamber? may have to go check the "shelf". I have so much Chevy shit that I should be dressing like Oroville Redenbacher 
I have some done and some not, but you can't have my ZL1 heads unless you have about $3500 you don't know what to do with... 
All I have right now is Oval ports, I think one set of "Opens" and one "Closed" chamber...the opens need to be freshened up which I can get done for a price...
I, for some strange reason though you were dealing with a Blue orifice...I mean Oval. 
GT
GT,
Hey there oval ports but dont know if there open or closed clue me in! I wanna say there open chambers but pistons are flat tops if that helps.The shop said I had deep chambers for marine use if that makes sense. So let me get this straight I dont have to worry about the casting #'S I can just bolt on any bb heads with matching ports I heard they can play a big part with the overall performance if you randomly swap them out?