head stamped P80 or P30 or P90

[MC75Z]

I just got a head stamped P80 but looking from different angles could be P30 or P70. Anybody know which it is and if it is a good head.

[Pir0San]

Probably a P90. P30 is a L24 block. Does it have hydraulic lifters?

[MC75Z]

PirOSan, It has an overhead cam would'nt know where to look for lifters.

[Pir0San]

Sorry, not hydraulic lifters, hydraulic rocker arms. Forget what I said earlier, you'd only have hydraulic rockers if it was a P90a. Chances are your head is a P90.

[beandip]

You mentioned that looking at the stamp from different angles the numbers could be a P-70 . Well there is a P-79 head . It is from a injected 280ZX If it is a P-90 as was stated before , that came from a 280ZX turbo. One thing , the P-79 has liners showing in the exhaust ports . The P-90 doesn't. Gary

[MC75Z]

Beandip, After seeing in the daylight it is a P90. How does this compare to an N42 or E88. I would be using it on a L28 with fuel injection or SU's. I have a 73 and 74 with L28's and SU's, also have a 75 and 77 with L28's and fuel injection. Would be using this as a back-up head. Thanks, MC75Z

[jfairladyz]

The P90 is the best flowing L head, out of the box. It has large valves and large square exhaust ports which help it to breath better then any head before it.

[beandip]

mc75z , The P-90 if not milled will give you vary low compression on your L-28 , because it has dished pistons and the P-90 is meant to run with a Turbo charger to boost the compression. It is a much better head than the other two you mentioned because it has a better designed combustion chamber and larger valves. If you were using a flat top piston block , 54 , block this would help. So if you have the head milled to boost the compression , it will be a good up grade. Not having done this set up . I am only repeating the information that I have learned . I am running a F-54 block flat topped pistons and a P-79 head , which was for a injected application . There are two different 88 heads , one from a '72z and the other from a '73 which is a emission detuned application with lower compression. Gary