TH400 to SM465 conversion - two piece driveshaft, front section length?

[bake315]

Hey guys,

I am about to swap an SM465 into my '73 crew, which has a two-piece drive shaft.  It originally had the TH400 in it, and so the front piece of the drive shaft is not the right length for the SM465.  I need to know what length the front piece needs to be in order to accommodate the SM465.  I figure there have to be some stock ones out there somewhere, but not sure as to their length.  If I knew the exact length, it'd be a huge help!

Thanks in advance for any info,

bake315

[bake74]

     There are a couple of versions of the 465 with different tail shafts available, we need to know what year 465 you plan to put in to determine how long you need to lengthen your drive shaft.

[bake315]

     There are a couple of versions of the 465 with different tail shafts available, we need to know what year 465 you plan to put in to determine how long you need to lengthen your drive shaft.

It's the one with the 10 spline output shaft - casting number 6273212.

Thanks, bake315

[bake74]

      Well I don't have a stock one, but the length of a TH 400 is 24.37" and the SM 465 is only 12".  So if you go off of this you would take the difference, but I would do the swap, measure the actual length, and determine how much slip/flex you will need and then have one made or yours shortened.

[bake315]

      Well I don't have a stock one, but the length of a TH 400 is 24.37" and the SM 465 is only 12".  So if you go off of this you would take the difference, but I would do the swap, measure the actual length, and determine how much slip/flex you will need and then have one made or yours shortened.

I guess I could do that.  When I was a kid, we had a 74 3+3 with the SM465 in it from the factory.  That's why I was thinking there should be a stock length front shaft out there to account for the longer cab & shorter tranny, and thus avoid having to lengthen the one I have.  Just didn't want to have to go through the whole rigamarole of guessing the specs and customizing a drive shaft, when there might be a 70's crew with a 465 and correct length shaft out in some junkyard somewhere, that would be ready to bolt on.

[bake74]

      Well I don't have a stock one, but the length of a TH 400 is 24.37" and the SM 465 is only 12".  So if you go off of this you would take the difference, but I would do the swap, measure the actual length, and determine how much slip/flex you will need and then have one made or yours shortened.

I guess I could do that.  When I was a kid, we had a 74 3+3 with the SM465 in it from the factory.  That's why I was thinking there should be a stock length front shaft out there to account for the longer cab & shorter tranny, and thus avoid having to lengthen the one I have.  Just didn't want to have to go through the whole rigamarole of guessing the specs and customizing a drive shaft, when there might be a 70's crew with a 465 and correct length shaft out in some junkyard somewhere, that would be ready to bolt on.

     I didn't say there wasn't one, I don't know if anyone on here will have run into that combo, so they might not speak up.  Have you tried to go the gm heritage web page in the tech section on here and look up the year of truck and see if the option was available, that would tell you if it was, then maybe you might get lucky and find one.

[bake315]

     I didn't say there wasn't one, I don't know if anyone on here will have run into that combo, so they might not speak up.  Have you tried to go the gm heritage web page in the tech section on here and look up the year of truck and see if the option was available, that would tell you if it was, then maybe you might get lucky and find one.

Thanks for the tip about GM Heritage.  Took a look and it was definitely an option.  I appreciate your input and suggestions!

bake315

[bake74]

Thanks for the tip about GM Heritage.  Took a look and it was definitely an option.  I appreciate your input and suggestions!
bake315

     Glad to hear it was an option, now hopefully you can find a truck that had that combo in it.