It sounds like your 80% there with pulling the motor down. I mean it's out of the car already and only a few bolts away from getting the heads off. Surely with all the effort you've put in so far you'd be itching to see what's gone wrong with your own eyes.

I reckon persist with the DIY to the stage where you take the heads off to look at the gaskets and deck surfaces. Hopefully then you can see what caused the failure and do a bit more research from there on how to prevent it from happening in the future.

As for the rebuilding part, ASG were the original builders. They should know what clearances they used last time and may be able to make suggestions for the future. But I can see how the turn around time is a bit frustrating.

Good luck with it!

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GOLD PIG STI