Won't run it had a bent push rod and we changed the whole head now when I hit the key the fly wheel just spends I think the timing is off and I'm not sure how to go about setting it should I take the engine off and then go from the bottom to get to the timing chain or go in through the head? I would be thankful for some help

Does not have a timing chain,unless you took the engine apart and turn the gears its still in time.did you set the valve clearance when you put the new head on , and did you find out why the pushrod bent ?