so today i took of the rocker assembly tore it apart and found no problems so i had a spare one and put it in and it still knocks

checked compression i have 170psi on all 3 and on 4th cylinder i have 155psi

is this variation normal?

I crawled under the car the knock isnt that lound from the sump its alot louder near piston 3 and 4 near the pushrods

i also checked the pushrods there all straight

can it be something like tappets or camshaft?

Thanks!