Ticking sound in engine while driving

1988 JEEP WRANGLER SAHARA 6CYLINDER SAHARA-JUST HAD ENGINE REBUILT-I CAN HEAR A TICKING SOUND WHILE DRIVING. COULD THIS BE SOMETHING TO DO WITH THE LIFTER STICKING

JUST HAD THE ENGINE REBUILT AND I CAN HEAR A TICKING SOUND. MECHANIC SAID IT WILL GO AWAY AS ENGINE WEARS IN. I’VE GONE 500 MILES AND THE TICKING IS STILL THERE BUT SEEMS TO BE GETTING LOUDER. IT’S A JEEP WRANGLER SAHARA 1988 6 CYLINDER AUTOMATIC. COULD THIS BE A LIFTER PROBLEM. I’M STUMPED THANKS JIM

A ticking could be a valve lifter. A proper engine rebuild means it should have gotten a new set of lifters. If they reused the old ones then I would question the entire rebuild.
Another potential source of a tick sound is a tiny exhaust leak between the exhaust manifold and cylinder head. This can sound exactly like a bad lifter.