All Pushrods Bent and Wrong

The previous owner replaced the timing chain on mine and it ran ok with the bent pushrods, never thought they were a problem. I put a 4 bbl manifold on and it ran terrible, that's when I decided to take a look under the valve cover and found every pushrod bent. I replaced them all and runs great now. I guess with the increased amount of fuel engine couldn't handle it and backfired to let me know I had a problem. Initially I thought I had an air leak so removed the manifold and that's when I saw the bent pushrods with the valve covers off.