My other ride, 96 mustang,4.6 is leaking coolant and overheated, at the rear around nipple on the plastic manifold. After pulling over, it was scalding hot, after letting it cool, it had only lost about 2 qts of coolant. The check engine light is on. I drove it home about ten miles,stayed in the middle of the gauge, seemed to run fine.My question is, how can I tell if there was any damage to the heads or head gasket? I'm preparing to do the PI intake manifold to non-PI heads swap, and want to make sure I don't have to do this job twice. Thanks