Where did my push rod lifter go?

I have a 1973 Ford f100 with a 77' 351 modified engine, after taking off my valve covers I noticed one rocker arm was loose. We saw that the push rod wasn't touching and was about an inch and a half away and it doesn't have a lifter… And I'm a little concerned as to where it could have gone… Please help… How harmful is this to my engine.

Could have tossed the lifter out of the lifter bore and it is laying in the lifter valley. At this point, I'd bet you have at least one totally worn cam lobe. Even if the lifter "collapsed" it only has about 1/8th inch plunger travel from top to bottom.

camshaftshaun@gmail.com

Check and see if the lifter just collapsed, but it's still in the bore.

Whoa! No lifter? Only one of two reasons that I can think of: Either the engine was assembled without it, or it split into pieces & is down in the oil pan. Either way - Not good.