94 hardbody has loud tapping noise

[808style]

i recently pulled out my ka24e enging from my truck to replace a broken timing chain guide and a rear main seal. and some other stuff on the engine. after dropping the engine in and starting it i found that it was making a loud tapping noise, which turned out to be a result of no oil pressure. so i fixed that problem.(small thin metal gasket o-ring thing that goes behind the timing cover and attaches to the block) i started it up and same thing, a loud tapping noise, but now i have oil pressure. so i took off the valve cover and found that one of the rocker arm bolts were stripped and that the cam had some light gouges from not having oil i guess. so i used helicoil to fix the the striped threads for the rocker arm and emory cloth to sand the cam. now every thing is put back and im still having the same irritating tapping noise. plus some white smoke coming from the valve cover.( fyi the white smoke was there from the first time i noticed the tapping sound.)
so right now i have no clue what could be the problem. and im really pressed for time on this. can anyone help?

ps. the check engine light is on.

[Rev_D21]

You may have air in the hydraulic rockers that needs to be purged.