Bore scope will only give you a visual of the top of the lifter cup...I have seen these lifters mushroom out on the bottom from the pounding by the cam lobe...
I would be removing the manifold...and try to pull the lifter out of the bore...check the bottom really close...if its pitted or you cant pull the lifter out of the bore...dont waste your time...just pull the engine and put it on a stand...you could have a real mess internally...
Iron Vortec heads are great street heads...you will need a different manifold but they are plentiful in aftermarket...and different rocker covers..Vortec are center bolt...
But watch out for Vortec truck heads...the ones with the hardened exhaust seats...they dont flow well at all...
and you end up with screw in studs...
