Driveshaft question

[72hemi]

Is a 340 4 speed Challenger driveshaft the same as a 340 727 automatic Challenger driveshaft?

[Moparal]

If they both came with an 8 3/4 yes

[72hemi]

Yep, both 8 3/4 rears, thanks.

[black71]

so what if i have a driveshaft fom an auto small block and am goin to an auto RB, wil it work?

[422STROKER]

If the SB has a 727 yes.

Tom

[black71]

schweet! so if i may ask...whats the deal with u-joints? different sizes and what not...will the ones already fitted hold up fine to my 440? if not what are my options for upgrades....i understand that they held up from the factory i guess i'm just askin if small and big blocks used the same size 

[422STROKER]

Should be a 7290 joint but could be a 7260, go for the non-greasable u-joints for strength.

Tom

[Chryco Psycho]

I would recommend the 7290 joint which is 2 5/8 " across inside the ears
 the other size is the smaller 7260 joint which is 2 1/8"

[black71]

k, will the 7290 work with my existing set up?

[422STROKER]

You'll have to check what you got for a rear end size.  If you find it is the 7260 then you can get the conversion joint to mate to it and keep the 7290 everywhere else.

Tom