I have an E88 head on my L28 motor. Someone has told me that the hot set up for my car would be with an E31 head. Currently in my 70Z I have an L28 block with the E88 head, 5spd, and a 3.9 diff. I'm running the original '70 carbs on the motor. From what I've read the E88 head has larger intake and exhaust valves, so I wonder does the E31 head have anything over the the E88?