yes, had problems with gaskets & head ,head sunk in chamber/head bolts became loose.in a short period of time.then changed head ,all good.

OK, I'm hearing the same thing from the V8 guys. If the head is softer than about 65 Brinell, the head bolt tension won't stay after torquing.

And that's one way to tell if the head is soft: if the head bolt washer has sunk into the metal suface.

While engine overheating won't soften the head, continuing to run the engine after the coolant boils away will bake it, allowing the head temp to rise above 250C and start softening the head. They said when it's soft around the exhaust ports, that's probably the cause, rather than overheating while machining the head (they heat the head to straighten it oldschool, or to fit guides or seats).

Unfortunately its the H89 that has gone soft. Spewing cause I paid $270 for it as a recently rebuilt head. It looks good!! Valves are all seated properly, nice springs, seals , welsh plug ect. So my next step is to pull the one off the car which is a round port plus I also have another round port on a running engine that is said to have bigger valves and some porting. This motor is down compression on no. 4 cylinder so I am suspecting something is wrong with it ?? Ill just have to have a look at what I,ve got and see what the best option is. Still spewing at the guy who sold me the H89. It's also been decked to 71.86mm. Thanks for all the advice. Will pull them both off saturday arvo n have a look. Thought It would be a simple new gasket H 89 on and go. I am tempted to get the H89 decked and see how it goes?? The didn't even know about soft heads that long ago and it is mainly around the exhaust ports in the middle.

when all the coolant is gone(after boiling 212deg) + the firing cylinder temp(1200deg).it can go well over your 260deg easy and soften the head.

You might want to look into an electroless nickel plate. Dunno how much it costs but that and heating the head to aluminium's diffusion temperature for a while might look. Maybe have a google. Probably more expensive than the casting is worth.

It's just a daily atm so just want to get it up and running as I am planning to an A15 turbo in later in the year so I need to go get the goodies. The engine did get real hot. so the head on there is probs cactus. The other round port I have is running and hasn't been cooked. Hopefully it will get me running if not Ill hunt another one down.