One set of heads I've used from Dart where the D4 heads, I was not impress with the results on that motor with those heads
I don't remember the casting numbers now, sorry
The D-4 heads were cast iron, raised exhaust port and for NASCAR racing. I think the nitro monkeys used them in the 1970s as well.
I was told by the owner that they where D-4 heads
, They were aluminum and had a raised exhaust port that was about half the size of a street hemi exhaust port. I wonder if they could have been the later D6 heads for Pro Stock?
His family owned several Chrysler, Dodge and Plymouth dealer ships in SO CA in the 1960s up to 2000 or so
I got lucky to be picked to assemble and dyno test that motor
