Author Topic: Driveshaft lengths  (Read 5376 times)

Offline Mhoihjelle

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Driveshaft lengths
« on: April 07, 2017, 07:21:16 AM »
Hey guys i am haveing a hard time finding out any info if my driveshafts will work 
I have a 1975 k20 4x4 dana 44 fr, 14bolt 10.5 rear,smh465,and 205tcase, i am putting a 6 in lift in and want to know will my driveshafts works if you dont have a k20 with the exact drivetrain as me please dont comment thanks for any info

Offline Captain Swampy

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Re: Driveshaft lengths
« Reply #1 on: April 07, 2017, 09:08:04 AM »
I think once you go past 4" you need to lengthen the drive shafts.
1987  350TBI 700R4  4X4  4.56 gears  33" BFG All Terrain


http://forum.73-87chevytrucks.com/smforum/index.php?topic=32209.0

Offline 1967KaiserM715

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Re: Driveshaft lengths
« Reply #2 on: April 07, 2017, 12:21:54 PM »
It's never about exact combo it's about actual lift. Generally you don't need to lengthen shafts up to 4", and I have seen instances were two near identical trucks needed slightly different shaft lengths to properly function.

The only way to know if a shaft will work is to measure BOTH compressed and extended lengths- this holds true with shocks as well- I just put add a leafs  on my truck, and while 90% don't use new shocks, my rears will not fit(too short).

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Offline Irish_Alley

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Re: Driveshaft lengths
« Reply #3 on: April 08, 2017, 08:35:23 AM »
dont know why you guys are commenting. the guy said he has a smh465, wont find anyone with that trans
If you canít tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline Irish_Alley

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Re: Driveshaft lengths
« Reply #4 on: April 08, 2017, 08:44:37 AM »
but seriously, each lift will be different, i have a 70ish k20 with a sm465/205 and 6" lift. the rear driveshaft will fit and so will the front BUT the front will be maxed out and will wear quickly. the splines will be the part that fails.

also if you havnt got the lift yet check out this
Lift kit Q & A

and

Cheapest 4" lift with skyjacker springs for under $700 with everything you need
If you canít tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline Mhoihjelle

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Re: Driveshaft lengths
« Reply #5 on: April 09, 2017, 04:19:15 PM »
Thank irish_alley for your info i will get a fr driveshaft before i install thanks again

Offline Irish_Alley

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Re: Driveshaft lengths
« Reply #6 on: April 12, 2017, 01:05:30 PM »
no problem. you might find one in the junkyard also. the 465 is i think the smallest trans so if you can find one for an auto then it should be a few inches longer, but be warned your truck SHOULD have the yoke style front shaft in 77ish they changed to a flange style. theyre not compatible even with a yoke swap, you can make it work but you need the front output shaft from the flange style and flange 
If you canít tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes