73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => 4 Wheel Drives => Topic started by: Mhoihjelle on April 07, 2017, 07:21:16 AM

Title: Driveshaft lengths
Post by: Mhoihjelle 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
Title: Re: Driveshaft lengths
Post by: Captain Swampy on April 07, 2017, 09:08:04 AM
I think once you go past 4" you need to lengthen the drive shafts.
Title: Re: Driveshaft lengths
Post by: 1967KaiserM715 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).

Sent from my LGL34C using Tapatalk
Title: Re: Driveshaft lengths
Post by: Irish_Alley 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
Title: Re: Driveshaft lengths
Post by: Irish_Alley 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 (http://forum.73-87chevytrucks.com/smforum/index.php?topic=31301.0)

and

Cheapest 4" lift with skyjacker springs for under $700 with everything you need (http://forum.73-87chevytrucks.com/smforum/index.php?topic=34074.0)
Title: Re: Driveshaft lengths
Post by: Mhoihjelle 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
Title: Re: Driveshaft lengths
Post by: Irish_Alley 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