I have a 2000 STS Cadillac my gasket is blown would it be good to just replace the gasket instead of buying another engine or what engine would be compatible to that engine

What gasket? If your talking about the Head gasket? You can replace it but when you do make sure you take the Head to a machine shop an have them check to see if it has any cracks or warped. If the head checks out ok then you need to buy a Head gasket kit for that vehicle because you will need to change many other gaskets for it as well. Replacing the gaskets would be cheaper to fix then getting another motor for that vehicle! Good luck.

I hear that the head gasket job on that car is expensive because it is very difficult , that is why most of them end up at the junkyard. but if you do get it done . I would see if there is a better alternative to the cheap stock one which gets destroyed after 100k