Questions about 68-72 / 73+ Leaf Springs - The 1947 - Present Chevrolet & GMC Truck Message Board Network

unixadm · 06-30-2005, 08:52 PM

I have a 72 C20 that was converted to a 4wd. They used 73+ differentials. I'm trying to determine what springs I need and if I can just buy a standard 6" lift from Skyjacker for a 67-72.

My rear springs are 52" from eye to eye and are 2.5" wide. The front springs are about ~47" long eye to eye and are 3" wide. Is this correct for my year truck?

**JIMs70GMC** · 07-01-2005, 06:41 AM

rear would be the same 69 and up except for the rare 56" spring on high gross weight vehicles.

For the front sounds like you have 73 and up springs. You'll notice they are 3" wide at the ends and 2.5" wide in the middle. All lift springs I've seen are 2.5" wide and make up the differnece with wider bushings at each end(1/2" v. 1/4" sticking out).

Also dana44HD is a 3/4 ton.

unixadm · 07-01-2005, 01:12 PM

So what is the proper spring sizes for a 72 K20 from the factory?

ryan68 · 07-01-2005, 01:38 PM

The front springs on a 72 should be ~44" long eye to eye.

unixadm · 07-01-2005, 01:50 PM

I'll have to measure again. Are the 73+ stock springs longer? I apologize for the dumb questions, but I'm having to try and figure out what the previous owner(s) did to this truck.

ryan68 · 07-01-2005, 02:18 PM

73+ should be ~47" front springs eye to eye.

unixadm · 07-01-2005, 02:21 PM

So then I should just go with a 73+ lift kit if I don't want to move the front spring mounts?

toroflow · 07-01-2005, 04:51 PM

MEasure the distance you have between the front spring mounts and the rear of the spring shackle to determine what length you need. It all depends on whoever converted your rig to 4x4, where they mounted the hangers. Measure to know this distance before you buy springs.

unixadm · 07-01-2005, 08:47 PM

I've got 52x2.5" in the rear, 47x2.75" in the front. I just measured it again. The front springs do not taper down to 2.5" - they are more like 2.75-2.85" all the way through. All I need to know is are the 73+ rear springs 2.5" wide? If so, then I should have no problems ordering a 73+ lift kit.

Thanks for the help guys.

**JIMs70GMC** · 07-02-2005, 06:56 AM

All I need to know is are the 73+ rear springs 2.5" wide? If so, then I should have no problems ordering a 73+ lift kit.

Yes

06-30-2005, 08:52 PM	#1
unixadm Registered User Join Date: Jun 2005 Location: Sacramento, CA Posts: 61	Questions about 68-72 / 73+ Leaf Springs I have a 72 C20 that was converted to a 4wd. They used 73+ differentials. I'm trying to determine what springs I need and if I can just buy a standard 6" lift from Skyjacker for a 67-72. My rear springs are 52" from eye to eye and are 2.5" wide. The front springs are about ~47" long eye to eye and are 3" wide. Is this correct for my year truck? __________________ - '72 Chevy C20 4x4 LWB Fleetside, 350/SM465, NP205, '73+ Axles (D44/14B FF 8-lug), 4 Wheel Discs - Updated Pics

07-01-2005, 06:41 AM	#2
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	rear would be the same 69 and up except for the rare 56" spring on high gross weight vehicles. For the front sounds like you have 73 and up springs. You'll notice they are 3" wide at the ends and 2.5" wide in the middle. All lift springs I've seen are 2.5" wide and make up the differnece with wider bushings at each end(1/2" v. 1/4" sticking out). Also dana44HD is a 3/4 ton. __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm

07-01-2005, 01:12 PM	#3
unixadm Registered User Join Date: Jun 2005 Location: Sacramento, CA Posts: 61	So what is the proper spring sizes for a 72 K20 from the factory? __________________ - '72 Chevy C20 4x4 LWB Fleetside, 350/SM465, NP205, '73+ Axles (D44/14B FF 8-lug), 4 Wheel Discs - Updated Pics

07-01-2005, 01:38 PM	#4
ryan68 Certified Chevy Man Join Date: Jan 2000 Location: Tucson, Arizona, United States Posts: 2,053	The front springs on a 72 should be ~44" long eye to eye. __________________ 68 Chevy CST (327,TH400) 3/5 drop lots of fun stuff 71 Suburban 4x4 (350,TH350) 7" lift 37's, D44/14 bolt and other sorts of goodies, lockers front and rear, flexes 40", 895 RTI score Check out my web site!!! http://www.geocities.com/cst68chevy/

07-01-2005, 01:50 PM	#5
unixadm Registered User Join Date: Jun 2005 Location: Sacramento, CA Posts: 61	I'll have to measure again. Are the 73+ stock springs longer? I apologize for the dumb questions, but I'm having to try and figure out what the previous owner(s) did to this truck. __________________ - '72 Chevy C20 4x4 LWB Fleetside, 350/SM465, NP205, '73+ Axles (D44/14B FF 8-lug), 4 Wheel Discs - Updated Pics

07-01-2005, 02:18 PM	#6
ryan68 Certified Chevy Man Join Date: Jan 2000 Location: Tucson, Arizona, United States Posts: 2,053	73+ should be ~47" front springs eye to eye. __________________ 68 Chevy CST (327,TH400) 3/5 drop lots of fun stuff 71 Suburban 4x4 (350,TH350) 7" lift 37's, D44/14 bolt and other sorts of goodies, lockers front and rear, flexes 40", 895 RTI score Check out my web site!!! http://www.geocities.com/cst68chevy/

07-01-2005, 02:21 PM	#7
unixadm Registered User Join Date: Jun 2005 Location: Sacramento, CA Posts: 61	So then I should just go with a 73+ lift kit if I don't want to move the front spring mounts? __________________ - '72 Chevy C20 4x4 LWB Fleetside, 350/SM465, NP205, '73+ Axles (D44/14B FF 8-lug), 4 Wheel Discs - Updated Pics

07-01-2005, 04:51 PM	#8
toroflow Registered User Join Date: May 2005 Location: Anaheim, CA Posts: 103	MEasure the distance you have between the front spring mounts and the rear of the spring shackle to determine what length you need. It all depends on whoever converted your rig to 4x4, where they mounted the hangers. Measure to know this distance before you buy springs. __________________ Ken '60 GMC 3/4T 4x4 '60 GMC Suburban 4x4 '64 GMC Suburban 4x4

07-01-2005, 08:47 PM	#9
unixadm Registered User Join Date: Jun 2005 Location: Sacramento, CA Posts: 61	I've got 52x2.5" in the rear, 47x2.75" in the front. I just measured it again. The front springs do not taper down to 2.5" - they are more like 2.75-2.85" all the way through. All I need to know is are the 73+ rear springs 2.5" wide? If so, then I should have no problems ordering a 73+ lift kit. Thanks for the help guys. __________________ - '72 Chevy C20 4x4 LWB Fleetside, 350/SM465, NP205, '73+ Axles (D44/14B FF 8-lug), 4 Wheel Discs - Updated Pics

07-02-2005, 06:56 AM	#10
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	All I need to know is are the 73+ rear springs 2.5" wide? If so, then I should have no problems ordering a 73+ lift kit. Yes __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm



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