Musta been some good times. Wish I was around to see those drive in diners and car lots full of classics. A lot more than just oil has changed.
It was great growing up in the car culture. My first car was a 34 Ford coupe I paid a whopping $10.00 for. My dad had a friend that saw the hulk sitting in the back yard and offered me a Corvette engine for free. Seems his brother was rebuilding one when he got caught with some drugs. He spent a few years on sabbatical at Texas taxpayer expense but I got the engine for free. By the time I got thru with it the car was one of the quickest around town. At 40 mph rolling speed it would still pull a wheelie. But to live thru the pony cars and the muscle cars was a neat ride. For me, it helped that I had an older cousin that was a super kinda guy and he also owned a speed shop. Machine work was cost of materials only. Parts were at cost but then again back then, a starter cost $15.00, a generator was $15.00, a high performance cam with a lifter set was under $50.00, 202 SBC heads were $25.00. So it really was not expensive to build anything back then. And best of all, you didn't need to be a computer nerd to work on one.
BlackXLT, you probably have a loose catalyst rattling around inside the metal CAT housing. I would suspect that sometime in it's life it got to see some major heat either from a rich condition or possibly oil going thru the engine.