The 65 caddy is a tank and would probably cost a whole lot more to restore both in money and man power than the Sprint, but if the caddy is special to you, keep it.
That caddy is a nice car, bet she has a smooth ride...I think if I already had a stang, I would keep the caddy, it's more rare and when the top comes down, the price goes up
I would keep the Cadillac. Especially if it is solid. Unfortunately, many convertibles were forced to sit outside in the elements for years. Tops leaked or rotted and leaked more! Floors rusted away.
That Caddy is the perfect VIP parade vehicle, I'd keep it, I'd think it's much more rare than the Mustang and looks to be in great shape. The challenge is storing that beast, looks like it needs an extra deep two car garage on it's own