I have a 74 Javelin with an un-original 304 in it, where do I find the numbers on the block to find out the date. I recently gave it a tune up and some roller rockers. Well I fired it back up and it seemed like there was a miss so I pulled the old Chiltons manual out to see if I had switched a plug wire or two. I put the plugs in that order and now the car won't start at all. The chiltons manual was from 71 and up. I don't know amcs too well so I don't know if the firing order changes after 71. Also I put the roller rockers on because there was a slight ticking and I thought the rocker ball was scored and worn it might be that. After I valve lashed the rockers and buttoned her back up there is still a slit tick. Maybe it was a different problem or maybe I didn't lash the rockers right. Can I open it back up and lash them again or will that make it worse. Some please help, I want to drive her before summer is over. Thanks