DOnt pull the head just yet. Remove the valve cover, use a wrench to turn the cam shaft over. Don't let the valve springs turn the cam and pull the wrench out of your hand and hurt yourself. if it turns all the way around, this is good. Turn it so one set of valves is closed and rotate the crank pully. feel for compression. Do this with each set of valves. If you have compression, your good to go.