All the mechanics are correct.When you turn the engine at the crankshaft bolt to rotate the new chain,the camshaft is not turning. Therefore the pistons will hit a valve that is open and this will lock up the engine. Just take a socket wrench and turn the camshaft as you turn the crankshaft. You will not need to remove the camshaft. This should be a fairly simple job if you are only replacing the chain.If you are replacing the chain rails and guides. Well, thats a lot more complicated and difficult job. They will only need replacing if broken or badly worn.You may want to check the chain tensioner and replace it if it needs to be replaced. Have fun! Wm. Lewallen...