bad lifter?

[v8s10kid]

i need some help from you guys and gals sence autozone seams to be hiring idiots now.

so yesterday i was driving home from work and i noticed a bad ticking noise. pulled over, popped the hood and listened, it sounded like the collector gasket but it was dark so i couldnt really tell 100%, i just babied it home and made plans to fix it this morning.

this morning i go out to my truck, checked the oil, ok (i changed it last week, pensoil synthetic). started it up. i got a tick when it first started but it went away after a second or two. checked it heard nothing weird. drove to work, some crap. first few miles were ok. hit the highway, still good. a few more miles later the ticking came back. pulled over and checked and it souned like it was coming from the back of the intake. coming home same thing.

i called my dad and had him meet me outside to check it but the tick stopped as i got to the stop sign 3 houses down from were i live . pulled the valve covers off and ran the motor, everything seamed ok. all the valves were opening and all the pushrods were spinning.

im stumped. i figured and bad bearing wouldnt go away and come back like that. same with an exhaust leak. i couldnt see or smell any antifreeze in the oil so i dont think its a headgasket.

so... lifter?

EDIT:
with my gear ratio i turn about 3000 rpm on the highway. and i had 50 psi oil pressure on the highway. 24 psi at idle. and temp never went over 170.