There’s worthwhile cast iron, W2’s and Chevy Dart Platinum, and then there’s stock small block Mopar heads. Not saying they can’t be made to work but it’s not enjoyable work. Heck even a 906 big block Mopar head can push the 290-300 cfm area.
They are date coded to the car so I'm more interested in optimizing them for a decent cam through the production exhaust manifolds , ported heads with a match ported intake etc... no going for all out power
