U Joint sizes: 71' Duster

1330s are definitely better than 1310s. 1350s are huge. I'd probably go 1330s on the shaft and use a conversion joint on the transmission yoke.

http://www.dennysdriveshaft.com/c150_combo_jt_1330_to_dodge_7260..3_58_outside_to_2_18_inside.html

Do you have the yoke with a joint to measure to verify which joint?