Never trust an engine that uses one bolt to hold the top and bottom together
I've had a few K engines and they have all been crap... And needed a lot of work done as soon as they hit 50-80K
When I first removed a head bolt on a K I wondered why it was 20" long?? When I was told not to spin the engine with the head off in case the liners popped out I realised just waht a shit desing it was. The coating on the ally is what gets skimmed off when you do a clean up.
The K engine seems to be a bit of a russian roulette engine. I've seen a good few that have made over 90K with no issues. I have seen a lot more that have not even made 50k before head work was needed. I also got involved in a real bargain last year on a T that had all the head work done by a proper engine shop. But the owner gave it away for pennies. Then I looked myself and found the coolant loss was down to the cheap steel coolant lines that run under the car. FFS these should be made out of stainless steel.