EmTee

Somebody probably lost their grip on the starter after removing the two mounting bolts and tipping it down to better access the solenoid wires during removal. That sudden pull on the wire likely broke green strands of copper...

The dual stripe is also interesting. I've never seen one with that style whitewall. Usually, the two stripes are the same width.

I recall my father's '68 Chevy pickup using the octagon key, but maybe trucks lagged in the changeover...

Check the left (and right) reaction rod bushings. Do you notice any 'pull' to the left when braking hard? https://forums.aaca.org/topic/171878-brake-reaction-rod-bushings/

This engine was completely rebuilt, correct? The timing was set to specification, right? Try connecting your timing light and watch the crankshaft mark as the engine runs. Does anything happen to the observed timing when the engine 'hiccups'? Also connect a dwell meter and watch that as well.

Uncle Rico approves!

Another option would be to contact one of the current area dealerships and ask whether there's a dealership association for the local area. If so, try to obtain a point-of-contact. If you're lucky, you may get in touch with someone responsible for managing whatever historical documentation or artifacts they may have.

I agree, those were likely '67 models produced during calendar year 1966.

Ha - I know the feeling!

Stupid plate tectonics!

Are you sure about '67 (ref. NTX's comments above)? Could it be a 'transition year' thing, where the GM keys were phased-in over 1967 production? All '67s (or, at least all Rivieras)?

Well, either that's not the original engine, or it was repainted in the incorrect color (should be silver). If the engine has been painted, then what else is not original paint? Of course the road wheels are not 'original' to the car either...

I thought PMs would work as long as @Specalist John initiates the conversation...

Beautiful! Now start testing that odometer!

The convertibles were all fitted with red leather.

Clean up and paint the odd wheel and then swap the spare onto it - problem solved!

Good -- that was a nice looking six-window Olds!

Seems like good money for that car. Hopefully the new owner gives it the attention it needs and doesn't just immediately attempt to flip it...

I did notice a little rust on the inside of the doors (e.g., rear corner of driver's door). Given the Ohio tags, I'd want to look underneath before making an offer. I had a '92 LeSabre Custom that looked and ran beautifully, but had to let it go after repairing brake lines and gas tank once the rocker panels started opening up...

Absolutely! As on my '64 GP...

Check that the backspacing is the same on the 'odd' wheel. What does the spare wheel look like? If like the other three, I'd make the odd one the spare.

For Buick stuff I usually check CARS and Bob's Automobilia. https://oldbuickparts.com/ https://bobsautomobilia.com/ If I still can't find what I'm looking for, There's Kanter and Fusick. https://www.kanter.com/ https://www.fusickautomotiveproducts.com/ Join AACA, BCA and or the GSCA. Then you'll get their magazine(s) with more specific parts and service vendors. Places like Summit and Jegs are good places to look for parts that are not specific to classic or antique cars (like the valve cover breather). When all else fails, post your question on this forum!

Hope so -- just bought this today (2023 Pace American 8.5X24 Enclosed Car Hauler)...

Correct - those two had exclusive use of that concave rear glass.

Nice looking Olds. These were good cars and I bet this one ultimately sells for considerably less than asking. Somebody will score a bargain. There's another 100K miles left in it with decent care.