what happened to my lifter/rocker arm??

Doesn't sound good. Either a bent pushrod, collapsed lifter, or a worn cam lobe.

i took it apart today... its a collapsed lifter.. only a teeeeny bit tho. anyways, i dont want to take apart the motor. it ran fine except for the noise where the pushrod hits the rocker everytime it moves.. anyways, a temporary solution we thought we would grind about 1/32 of an inch off the bottom of the fulcrum thing that holds down the rocker.that made it so that noise stopped cuz its snug like it should be. now it backfires. i pulled it apart again and made sure they were torqued right and they are. still backfires on that 1 cylinder i would assume. how can i fix this without taking the heads or the lower intake off? temporary fix is fine... please help!

I'd guess that the exhaust valve is no longer seating properly due to the grinding off of "fulcrum thing".

Try a shim underneath the fulcrum. Set your valve lash to zero, +