Does anyone have a suggustion as to what the next upgrade on a ZZ4 should be? The motor right now is being ran as is out of the box. I would like to upgrade it in the future.

:D

Head porting, valve springs !!!!, camshaft, rocker arms

How about GM's Hot Cam kit?
I've used one before in a ZZ4 with satisfying results.
All the goodies, reasonably priced, in one package and it's GM engineered.

Recurve the dist, from stock to begin with. Mine wasn't getting the timing in until 5000 RPM. Too much Vacuum advance too. Performer RPM, Hotcam kit, Port the heads, and you're looking at around 420 HP. I think the heads are the biggest restriction to power on the ZZ4. Cast iron Vortec heads make more power on the ZZ4 than the L98's do.