To the OP I say pull the cleaner looking head, check it for leakage and straightness. If within spec install it on the engine with a new head gasket. Then do a cylinder leakdown test or even a compression test. That will tell you the quality of the piston ring seal but nothing about the rod bearings. Checking those would require pulling the oil pan and checking every rod for looseness.
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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "