1968 Oldsmobile 98 Purchase advice

Hello i'm deciding between two cars, which one to buy. The first is a 1968 Oldsmobile 98 coupe and the second is a 1970 Buick Riviera. They both have 455's under the hood, and I think gm used the same 455 engine for both olds and buicks during the era.I plan to give the car to my wife, as she has complained her current daily driver (1999 chevy malibu) lacks power and trunk space. So i've decided to get her a old school V8, that is big and powerful. If it was me I would get the Olds, as it is more comfy and harder to find than a Riviera. Since i'm not the one who will be driving it, I would like a indipendent opinion about the cars i'm considering to purchase. Any advice as to which car is the better choice would be greatly appreciated. Thank you.