How can you tell if your engine is non interference?

How can you tell if your engine is non interference?
If you give the yr/make/model/engine, could let you know... But if you want to find out your self. You need to turn piston 1 to TDC and depending on the engine, undo the valve spring keeper and measure how far the valve drops until in hits the piston. Subtract .050 of an inch and if it is less than the max valve lift you have an interference engine.