Things to remember on these era tight engine compartment trucks is oil pumping issues. Many 5.2's are junk from running a bit hot and the oil pump goes into bypass and the engine oil light comes on. If your running at 75 MPH when it looses oil pressure....
I've taken valve covers and intake manifolds off to find 2 inchs of coked oil. We even pulled one apart that had a snapped camshaft due to binding in sludge.