I have been out of the hobby for about 2 years and am going to get back to working my 64 polara this weekend. I am going to start with swapping in a late 60's b body rear end (drum to drum) so I can get rid of the tapered axle rear that is in it now. I would like to keep the original SB trans for the time being and was wondering about the U joints. My question is will the old trunnion drive shaft fit into my later 60's case? I don't remember if its a 489 or a 742, but I will see this weekend. Any thoughts would be greatly appreciated.

Thanks,

Matt

there's 2 sizes of ujoints: the "small ujoint 7260" which fits a flange w 2&1/8 inside to inside of the ears and a "large ujoint 7290" w 2&5/8. if the rear end yokes on the old/new pinion is the same (large or small) you're set and if not ask your parts house for a Mopar 7260/7290 combination ujoint. Several brands (spicer is excellent) and orient it so the zerk is being compressed (visualize the input half of the ujoing being turned CW) and for a HP app a non greaseable ujoint is preferred (no zerk) and you pull the caps & grease it before installing and dissassemble/regrease at regular intervals. It will have no hollow internal passages for the grease & therefore is much stronger. For your app a Spicer w the zerk is an excellent choice

As long as the yokes are the same it bolts right in.If they are different you need the dual joint.I have a 69 rear in my 65 with the OE shaft.My kids 62 300 we were running the OE shaft with a 69 C body rear.Rocky

my 67-polara 742-3.23 8 3/4 chunk had the odd ball 3 5/8/1330 corse spline yoke-has end tabs along with straps to hold it in(no c-clips on caps)

I crossed it with a 7260x1330 conversion u-joint
so there are 3 size u-joints

7260/7290/1330

Thanks for the info I will check it out tomorrow