318 help

so i just swapped the stock cam in my 318 to a comp cam that is 268/268 duration and 454/454 lift. at the same time i put on some heads that have been opened to 1.6 on the exhaust and 2.02 on the intake and put on a freshly rebuilt holley 650 vacuum secondary. now when i go to start it all it does is turn over it wont catch and run. i already checked for spark and fuel. any ideas what it could be the only other think i can think of is timing