I recently picked up a 70 series 1 and was going through the receipts that came with it and noticed that during a rebuild in 78 the owner had to replace the head. This prompted a mad dash to the garage to see if they found a e31 head or bought an e88. Its an e88. My questions start with this one: If the head was replaced did they have to replace the intake and/or exhaust manifolds too? I think the intake manifold says e48 on it. Any benefit to picking up and rebuilding a e31 head? (performance, value, gas mileage, etc.) TIA John