The car came with a bunch of receipts from the PO going back a year or too. Here is what seems to have been completed.
- A bunch of work on the engine: Valves, springs, new cam and bearings, gaskets, oil pump kit
- The radiator was either refurbished or replaced
- Driveline center support and bearing, ujoint
- Remanufactured power steering box (maybe: https://shop.advanceautoparts.com/p/cardone-power-steering-gear-27-6529/3790142-P)
- Remanufactured power steering pump https://www.oreillyauto.com/detail/b/lares-corporation-5725/suspension—steering-16778/power-steering-16478/power-steering-pump-12580/3d51bc7abdc5/lares-corporation-power-steering-pump-remanufactured/2178/5763968
- Brakes were turned (I wonder if original Al-fin or replacement iron drums)
- New transmission mount, new flex plate, rebuilt transmission
- Cylinder head gaskets https://shop.advanceautoparts.com/p/felpro-cylinder-head-gasket-set-hs-7922-pt-1/19782465-P
- Crank bushing
- Thermostat https://www.oreillyauto.com/detail/b/plus-4222/cooling—heating-16773/thermostats-25043/thermostats-12876/82bbe83f6a70/murray-plus-thermostat/3478/4436173
- Temperature sender https://www.oreillyauto.com/detail/b/standard-ignition-5753/engine-sensors—emissions-25132/engine-sensors-25049/coolant-temperature-sensor-sender-switch-11362/aec49c4ca931/standard-ignition-2-terminal-coolant-temperature-switch/ts15/5825312/1965/buick/riviera?q=TS15&pos=0
- Oil pressure switch https://www.oreillyauto.com/detail/b/standard-ignition-5753/lighting—electrical-16777/switches-16486/engine-switches-25047/oil-pressure-sensor-switch-12875/caee72c68788/standard-ignition-1-terminal-oil-pressure-switch/ps15/5815754
- New alternator https://www.oreillyauto.com/detail/b/ultima-4536/charging—starting-16772/alternator-11425/f7cab2ae3cc0/ultima-55-amp-alternator-remanufactured/r111616a/4603150
- New Torque converter (no core)
- Transmission cooler line
- New battery
- Rebuilt brake booster and master cylinder
- New ignition switch