convertible - drive it home

Buick Electra 225 convertible.
Original condition, possibly a one owner vehicle, recently out of storage.
We have cleaned it up and polished the paint.
New battery and cables, new starter, changed oil and filters; running and driving, brakes work, top works, all the electric windows work.
Engine has knocking noise that comes and goes.
Please call me for details and additional photos. Tracy Kroon 406.578.2000