desperatly need engine help

ok so been rebuilding the 318 for awhile, got everything all back together, when manually turning the engine before it was installed the thing sounded like it had great compression, we followed the book when putting the engine together, but now the thing is in the car, we try starting it up, nothing. have spark, adjusted timing, have fuel..checked compression in cylinder 1...zero. took off valve covers on both side, almost every pushrod was bent. the lift on the cam is .474, i know i dont know what im doing all that well so im mostly just listening to different people, some one told me thats a lot of lift, some guy today told me thats not much oversized at all. now im trying to figure out how to fix this and get the thing running soon. do i need shorter pushrods? adjustable rockers? different springs? valves were all redone before heads were on, not hitting piston, what do you guys think would the best way to go about this?