1984 Ram Crank No Start

You're assuming it's the ignition. I have 73' Dart sport 340. I did a bottom end rebuild with a new thumper cam and left the Heads alone, Big mistake! Car started right up and ran to break Cam in the took it for a drive. The next time I tried to start nothing, just cranked. Ignition and fuel checked out. It Turns out the INNER SPRING ON THE #4 EXHAUST WAS BROKEN! Replaced all the springs and valve guide seals and It started right up and runs great!!!!!!!