Bob, maybe you can hook a vacuum gauge to the glove box unit to see how much vacuum it makes and then hook a mite vac to truck unit and see what it requires . This should help tell what end needs work.
Kevin
I'm sure you could easily spend that much to restore a car like that. The hard part is getting back what you paid to have it done. Beautiful car.
Kevin
When I first got my '63 riviera I had to constantly correct the steering. The bushings on the pan hard bar were worn out. Replacing them made a big difference in how the car handled .
Kevin
Bob, my car will read 18 to 20 psi at idle and 40 at highway speeds, once its warmed up. Cold the pressure is higher. My old Pontiac with a 455 would read 10 to 15 at idle, no problems
Kevin
Everything was easier 40 years ago. Things I used to do in a hour only take a day now. Working on old cars now is still fun, just takes a little longer.
Kevin
I think it more important to look at how often you change your oil than the type. I use valvoline vr1 but I change the oil at least one a year regardless of the miles. With synthetic oils they call for longer intervals on oil changes. My vehicles sit during the winter months and I don't want the dirt and moisture sitting in the engine all winter. The pervious owner of my riviera used Mobil 1 and said it was the only type of oil used since he rebuilt the engine. One of my first projects after getting the car was to change the lifters. It sounded like a $100 dollar beater for about 3 or 4 minutes when started. The lifters were not worn but I was surprised there was a little sludge in the lifter valley. No problems since changing lifter and oil.
Kevin
At one time I would have agreed with you Winston. AC used to spend more for the raw materials to make a filter than competitors had in the finished product. AC is long gone and gm service parts buys from who knows where.
Kevin