20V head

[BCKLUP]

Why not put the 20V head on a 4A-GZE block....best of both worlds. The best 4A head on the best 4A block, forged pistons, oil sqirters, etc.

[4Aaron GE]

Becuase they were built for two different applications.

The 20V head was optimized for N/A use (high overlap cams, etc)
The GZE block was optimized for boost use. (low compression, heavy internals)

So unless you get some custom cams made up, it probably wouldn't reach full potential. This isn't to say that it can't be done, just that it'd take a lot of effort.