Clutch diameter differences?

Gang,
For the first time in the 31 years I have been driving this Dart, I have actually worn out a clutch. The car had a 170 originally, and I put a 225 in it a couple of years ago. In the last month or so it slips sometimes at ~30 mph, which I am told is indicative of a clutch going out. My Haynes lists 3 different sizes for the clutch, 9-1/8, 9-1/4, and 9-1/2 inches. Can I "move up" to a 9-1/2" clutch without any problems? The flywheel behind the 225 is the one from the 170, as the 225 was originally in front of an automatic.

Thoughts and advice are appriciated.

Thanks.

Bill Rock
68 Dart, slip sliding away...