[SS Shaun]

ok ladies and gents i got my 454 running but i was told that that i need to have my valves adjusted because i had some back fire in my carb. now i looked it up online and a few friends told me that it needs to be
24 on the intake and 28 on the exhaust.
but then i had a few friend told me that it needs to be 1/2 turn pass zero lash. which one do i listen to?
its a hydro flat tappet lifter and cam setup i am a little confused as to what to do