Two Barrel to Four Barrel Upgrade?

I did the same thing only used an air gap Edelbrock and a 1406 Carb. Car ran ok with 2 BBl. P.O. replaced timing chain. I also thought vacuum leak. Took manifold off and saw all the push rods bent. Replaced all of the pushrods and runs great now. Some rods were bent pretty bad and others just slightly. Maybe chain broke and free wheeled and valves hit the pistons. When hot just turn the key and fires right up. Also a 74 318.