Head gasket

I beliee on a 94, it may be best to remove the engine out the top. As far as doing the work with engine in the vehicle, it could be done, but I wouldn't recommend it. What you are going to find, is this. Yes, you have blown, or leaking, head gaskets, you have determined that. This in most cases, is not a result of a fault with the gaskets themselves. It is a fault with the threads in the block, they were manufactured as part of the block and are aluminum. They give up, and the clamping is lost. This may have happened on one, or many, I would bet on this. Depending on the history(or the unknown) of this engine, repairs of this nature may have been performed, and that adds another complexity. What it involves, is installing thread inserts to replace the aluminum threads, and there is special tools and procedures involved. You may be able to find more information by searching 'timesert', that is what the insert is dubbed. With this information, you will at least be prepared for what may lie ahead.