Output Shaft Bearing

Trying to help out my boyfriend here. He's in the process of getting a small block 904 put together for the 360 going in his 67 Dart. He got this transmission free from a friend and it was missing everything within the tail shaft area. He has a busted 904 from his slant from the same car (doing a swap) and figured he could swap everything over but the output shaft bearing is too loose on the shaft for the small block trans. Figured he should just replace it but we're having a hell of a time trying to find the right one. I've measured the shaft on the trans with a micrometer and it averaged to 1.1650". Where would be the place to find such a bearing? Should the bearing even be different between the two 904s? This is our first time working with transmissions like this so help is appreciated.