Yes this is the same head that has the good port work on both intake and exhaust. The ports are also matched to the gasket. And yes, the head has hardened seats, and good guides. Yes the head has small hairline cracks in 2 of the waterjacket holes and one between the valves on the #1 cylinder. The head was pressure tested and there was no leak in that chamber. You might lose very little torque on the low-low end because of the exhaust, but that is mostly dependent on what type of cam you will be running. No this head has no towers, but you can remove the towers off of any of the 70-83 Z heads and they should all be interchangable. The towers that were on the N-42 were actually directly transplanted from a P-90 head. Do not worry about losing any low-end torque, you will not be racing at 2K RPM. This head will give you considerably more power, I guarantee it. It also comes with the Stainless Steel exhaust valves so you will not need to do any valve job work on the exhaust. I am not sure if you will even need to do any valve job work on the intake seats when you put in your intake valves. I was quoted today $125 to weld all the cracks and resurface the head another .003".