I had to have the seats redone when I got the car as the material was worn out.
I replaced the radiator, water pump, fuel pump and fuel tank.
It's a great car, very fun to drive.
The engine never overheats, the transmission shifts smoothly, it has powerful brakes for a 60's car.
The suspension is smooth, but it's still very agile for a large car. All accessories still work after 42 years.
This car is very powerful and reaches top speed of 125 mph.
I use it everyday during warm seasons and I can say it's the most reliable car I ever had.
It sounds like you really like your 64, we had a 63 like that when I was younger, wish I had it now, I loved that car too. Buicks always have been a classy car and still are.