mine are 10x18 on the back and i really think they look tiny ... like pizza cutters . I am looking forward to get my 10,5x19 or 10,5x20 Breyton Spirit Black
i think you can easily squeeze 10,5 inch with 275 or even 285 on the back of a 1971 nova depending on how low you want to go.
on the front i have 8,5x18 wanna upgrade to 9,5x18 ...
you know BMW wheels fits great on chevys because of the bolt circle, and depending you choose 3 series or 5/7 series you get all kinds of backspacings and it is easy to find the right rim.