compresion test and leak down are the best option but there is things you can do, get a manual vaccum pump, find a vacum port( use the brake booster one, its safe) connect the vaccum and read at idle and different rpm range, that gonna give you and idea of ur engine, also you should have a port in your valve cover(not pcv valve), disconnect the hose, put ur finger covering the hole and wait a few with the engine at idle if went you put off ur finger its a lot of gas pressure or a while smoke ur rings are fried, hope this can help you