Unfortunately, the ZC32S head doesn’t have all exhaust manifold holes drilled and tapped – unlike the ZC31S. I only heard about this reading the documentation from the shop in NSW (One Stop Mechanical) that originally fit the turbo to the ZC32S I purchased the kit off. I later confirmed this was the case when I removed my extractors from my current setup.
I did my best to mark out holes but wasn’t entirely happy with how I had measured and drilled.
With how tight the holes on the HKS manifold are to the M10 studs, you don’t get much allowance for error. With this in mind, I decided to only tap the 4 extra holes to M8 (instead of M10) to give myself a bit more room to play with. This worked out great.
My only remaining concern is the depth of one of my drillings. It’s 1-2mm deeper than the factory drillings. Looking at the casting, I think we are fine. Famous last words?
