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See solomiata.com - quite a few changes but the heads are interchangeable (along with the intake manifold)

The NB has a much better flowing head.

The bottom ends are fairly similar, but the NB runs higher compression.

yeah the NB8A has a better flowing head, higher compression, and a different intake manifold. The intake manifold has butterflies in it the open up at a certain rpm creating better mid range torque. The engine also no longer uses a cam angle sensor..

I think you should sell it..

NB engine also has solid lifters