I have a 64 oldsmobile dynamic88, and I am trying to convert my drum brakes to disc brakes. Can someone let me know what late model olds can I get get the front spindles,rotors, calipers and steering knuckles from.(front)

 

There are no "late model" spindles that swap onto the 1961-64 full size cars. Aftermarket kits are your only option.

 

And, my understanding is that installation of an after-market kits mandates changing over to 15" wheels.

 

That depends entirely on the particular kit. Many disk brake kit vendors say use 15" wheels simply to avoid having to educate people about the differences in GM factory 14" drum-brake vs disk-brake wheels. Lots of cars came from the factory with 10.75" rotors and 14" wheels.

 

Ok thanks for the information.