hey these d3ve a2a irons get a good wrap on you tube and other forums ,just some patient work can really arc them up for factory head,the d3ve a2a is the first of the emission heads with a big bump on the exhaust which must be blended at least or removed as it has something to do with emissions,on the intake side they only need a clean up,but the exhaust is choked and needs some nice porting ,even most go the cobra jet exhaust gasket mark it out and start grinding,they are around 92 cc to 97cc and with a sealed power flat top gets you into the 10.1 zone with milling of avarage 30 thou to get zero deck,but the earlier DOVE AND other early cast irons have a closed chamber and an easy 10.5.1 is had but too much if anything these days,factory cobra jet irons are hard to come by even in the states,very interesting all this big block stuff.