Thanks Rhys -

Went and checked and there is an O2 sensor on the exhaust manifold, so I think you are right in that a replacement header pipe and cat came from some other vehicle. That would explain the problem I have with the first muffler connection to the cat pipe.

Unless the '88 had O2 in manifold & just before cat? But the engine runs good and idles fine. The temp gauge appears to be acting up, even after thermostat change. Holds steady at either 11 or 8 O'clock. Hopefully just a curcuit board problem.