Brinell testing overheated head castings?

[Chris Wilson]

I have a couple of RB25DET heads here, one of which I KNOW has been overheated through water pump failure, the other is of unknown origin. I don't suppose anyone has Brinell testing hardness figures for a known good head available, have they? Here in the UK the Cosworth Sierra engine in turbo form regularly used to overheat and figures for a good head versus a "cooked" head are available. I don't want to waste money and time modding a soft casting. Was hoping someone had Brinell figures for the Nissan castings? Thanks.

[ace_nz]

120 is hard, anything less than 70 is getting very dodgy, the bolts will pull into the head after a while and clamping load is lost. Id be checking for bend through the cam tunnels, they may need line boring.

[Sydneykid]

With overheating I have not found hardness to be an issue, as ace_nz posted the usual problem is straightness.