Another way is to remove the right valve cover and check the right cam timing mark when the crank is at TDC. It should be close. Number one lobe positions should look like what has been described as "bunny ears".

After you get the distributor in correctly rotate the crank and bring the cam mark into alignment. Look at the crank timing mark to measure the stretch. If more than 8-10 degrees timing chain service needs to be done.