Driveshaft and tranny crossmember

The small u joint is also called a 7260 u joint, it measures 3 3/8" across. The large u joint is also called a 7290 u joint. It measures 3 3/4" across. I've seen many 340 and 383 cars come with the small u joint, not to mention 6 cylinder and other small blocks, so it is usually the more prevalent one out there.
Glad the collars got there with the extra goodies...