difference in 67-72 trucks - The 1947 - Present Chevrolet & GMC Truck Message Board Network

darksaga · 09-07-2003, 11:33 PM

I know the front leaf spring mounts are different in 67-69 and 70-72 but is the rear front shackle different too?

the rear springs are in a way too but in what way, I have a 68 3/4 ton but my rear axle is out of a 73 the differance as I understand it is the centering pin is different on the mounting pad?

breeh · 09-08-2003, 12:56 AM

The spring length is different in the 67-8's on the rear. The spring length is the same as 73 to whatever but it is the position of the centering pin on the spring that differs from 67-8's. This is why they cannot be used. The mounting pad position has nothing to do with any of it though.

Pont · 09-08-2003, 08:59 PM

If I understand what your saying correctly, there should be no problem mounting a 73 rear axle under your 68. The difference come when you try to stick 73 rear springs under your 68. The 68 rear springs should be 56" from eye to eye and the axle centering pin is dead center in the spring pack. In 69-72 and maybe 73 up (not sure on the later years) the rear springs are 52" from eye to eye and the axle centering pin is NOT centered in the spring pack. The centering pin is set forward, therefore causing the axle to sit further forward and not center in the wheel opening. The later model springs can be used but you will need to relocate your spring hangers on the frame, basically move the fronts back further til your wheels are centered in the opening and then see where you need to hang the rears, depending on rear spring length.

If you stay with the stock 68 rear springs in your 68, you shouldn't have much trouble getting most any other axle mounted under it, other than a possible pad relocation. You guys that know a lot more than me, feel free to chime in and let us know if there are major differences with the 73 up axles as far as mounting in our 67-72 trucks.

darksaga · 09-08-2003, 09:07 PM

I get it now I took it that the centering pin was offset to the side not front to back, I was thinking why could I not just drill a new hole. Makes sense now

Pont · 09-08-2003, 09:23 PM

I'm glad it makes sense to you because I got a headache reading my own post

Just read Breeh's posts from now on and ignore mine. Breeh's the man and knows what he's talkin about.

darksaga · 09-08-2003, 09:30 PM

I understood It fine, you wrote like I do at times (before editing)

now on the front brothers list the front rear shackle as being the same from 67-72 but ord lists thier shackle kit to only work with 69+

I know the front fixed shackle is diffrent and I have a wtb in parts for sale for them right now

would the only reason the ord kit would not work be becasue of the front bushing? their kit comes out to be cheaper then brothers and I would rather use the kit due to upgraded parts

Pont · 09-09-2003, 01:29 AM

I believe your right that the only difference up front is probably bushings. When I ordered my front springs, I ordered them for the 69-72 and they bolted right up to my 67. I believe that the 73+ will bolt in place as well. I'm not sure what the difference could be. I would just measure your fronts, and compare with what you want to replace and see if they will interchange.

darksaga · 09-09-2003, 12:31 PM

breeh, pont thanks for the info

more questions though

iirc you are useing rancho 9000 shocks?

they don't list an application for 67-68 did you use the one for 69-xx?

Pont · 09-09-2003, 08:16 PM

Yep, I used the 69-up shocks on my truck and they worked perfect, well almost perfect. The front shocks bolted right in and work great. The rears that I got (listed for an 8" lift) were about 2" short of mounting with them fully extended. Well that wasn't gonna work so I got into the Rancho catalog and found the longest shock they make with the correct ends that I needed. Returned the ones that were too short and ordered the long ones and they work great. I can honestly say that my truck rides better now than it did at stock height.

darksaga · 09-09-2003, 08:32 PM

thanks for the info

once I get the chevelle back on the road I will probably put a bigger lift on (it has a ~2.5" on it now). For now Im going to just replace the bushings, I found a place that had them in stock today and they should be here by tomarro

I only plan on going with a 4" or so lift but even for that It looks like im going to need a longer driveshaft with the 2.5" the shaft is only in ~1/3 of the way

bigger=better · 09-09-2003, 10:30 PM

Hey guys,

Newbie here. ?I've been reading posts as research for my project and came across this one. thought I had what I needed now not so sure.
I have a '68 4X4 suburban 1/2 ton and '75 3/4 ton axles (14 & 10 bolt) with springs, and th400 and TC (NP205?) that I want to swap in. Suggestions? Tips? Bad news?
I am also swapping in a Mark VI 454.
I am a capable mechanic just not familiar yet with old chevy 4X4s

darksaga · 09-09-2003, 11:19 PM

horde parts
as for swaping a big block in mine was done before I bought it

a few members here have done the swap,

mine looks like it wasent that hard, the pass side framerail is ground out abit other then that the swap looked pretty easy. IIrc you need a 2wd big block engine crossmember

anything will fit with a sawzall and a bfh

happy building

Pont · 09-10-2003, 08:51 PM

bigger=better,
I don't see where you are going to have any problem using those 75 3/4ton axles but you might be SOL on the springs. Take the front springs and measure from eye to eye at the bushings. They might be the same length (check the width also along with the location of the spring centering pin) and you might be able to use the front springs. I can almost guarantee that the rear springs will be different in length and that the centering pin will be in the wrong location. You can use the 3/4ton rear springs but you will need to relocate the spring hangers to a different location on the frame. Both front and rear hangers!

Hope this helps............

bigger=better · 09-11-2003, 03:45 PM

Thanks, That is what I thot I was gonna get from what I read in the previous posts. Kinda wanted those heavier springs too. So I may try moving the hangers.

Pont · 09-11-2003, 09:05 PM

Keep us posted on your progress. Good luck with your project.

bigger=better · 09-11-2003, 09:26 PM

OK, Maybe I'll post a pic or two tomorrow.

**JIMs70GMC** · 09-12-2003, 05:11 AM

Those 1975 springs won't work on the 68 they will be about 3" too long in the front. For the rear you have the pin location and length of spring to look at could be 56" or 52" springs w/ the 1975 axles.

HeavyK20 · 09-12-2003, 12:02 PM

Speaking of springs...has anyone noticed that there are 2 versions of the forward spring hanger on the rear axle of a K20?

Version 1 has a small mount that does not hang below the frame rails.

Version 2 has a large mount that is about 8 inches tall and hangs below the frame rail about 3 inches.

There is a 2 inch differnce in the actual height of the spring bolt.

Does anyone why there is a difference?

bigger=better · 09-12-2003, 08:00 PM

Well here she is. Would you give $50 for her?

bigger=better · 09-12-2003, 08:02 PM

and again.

Pont · 09-12-2003, 08:43 PM

Oh yeh, I would give $50 for her several times over!

bigger=better · 09-13-2003, 08:37 AM

I am sure you don't need me to confirm it but you're right, these springs ain't gonna work.
Yeah I gave $50 for her, and another $15 for a beat up 2wd L6 with no front clip that can just be seen in the background.

darksaga · 09-16-2003, 02:23 PM

I checked the part # from the front shocks I have now 5113 and the rancho app guide lists them as 67-72 2wd, 81-87 4wd, chevy luv 72-83 so I guess almost any shock would work

the ones in there right now are so shot they don't rebound at all anymore but I never noticed the front springs are so stiff (stock with add-a-leaf) I never noticed. New springs here I come

J.Lance · 09-16-2003, 05:52 PM

Quote:

Originally posted by HeavyK20
Speaking of springs...has anyone noticed that there are 2 versions of the forward spring hanger on the rear axle of a K20?

Version 1 has a small mount that does not hang below the frame rails.

Version 2 has a large mount that is about 8 inches tall and hangs below the frame rail about 3 inches.

There is a 2 inch differnce in the actual height of the spring bolt.

Does anyone why there is a difference?

I've actually noticed that difference in hanger between two blazers. We racked our brains trying to figure out the springs. There had to have been two different spring versions as well. Previously I thought all the 69-72 Blazer rear springs were the same until I saw the different hangers, exactly as you described. Don't know why the difference.

bigger=better · 07-02-2004, 09:04 PM

Finally got the 3/4 ton axles under her!

The front went in no sweat, had to move the spring perches in on the backend

first time I ever moved perches, was easier than I thought.

454 is finished(basically), need new case for my th400 then I can move forward again.

Unfortunately that will probably this time next year as I'm going to be gone the next several months

happy to be this far at least

09-07-2003, 11:33 PM	#1
darksaga Registered User Join Date: Nov 2002 Location: santa cruz cali Posts: 118	difference in 67-72 trucks I know the front leaf spring mounts are different in 67-69 and 70-72 but is the rear front shackle different too? the rear springs are in a way too but in what way, I have a 68 3/4 ton but my rear axle is out of a 73 the differance as I understand it is the centering pin is different on the mounting pad? __________________ 1968 gmc 3/4 4x4 longbed. built 469 700r4 (needs a th400 REAL SOON!), 14bolt ff rear 73 3/4 dana 44 1970 chevelle all wheel disc, tubular rear control arms tall spindle swap up front matching #'s 350 work in Progress

09-08-2003, 12:56 AM	#2
breeh Recovering 67-72 Addict Join Date: Oct 2000 Location: North Bend, WA Posts: 1,788	The spring length is different in the 67-8's on the rear. The spring length is the same as 73 to whatever but it is the position of the centering pin on the spring that differs from 67-8's. This is why they cannot be used. The mounting pad position has nothing to do with any of it though. __________________ 68 Short Fleet 4x4; 427; BTO Level 3 700R4; NP205; Dana 60 front and rear; 4" lift with 35's; Disc brakes; AGR variable ratio steering; factory bucket seats; factory tach and tilt. "Friends call me cruzer cuz I like fast cars and fast women"

09-08-2003, 08:59 PM	#3
Pont I need another Barley Pop Join Date: Feb 2001 Location: Grants Pass, OR Posts: 1,629	If I understand what your saying correctly, there should be no problem mounting a 73 rear axle under your 68. The difference come when you try to stick 73 rear springs under your 68. The 68 rear springs should be 56" from eye to eye and the axle centering pin is dead center in the spring pack. In 69-72 and maybe 73 up (not sure on the later years) the rear springs are 52" from eye to eye and the axle centering pin is NOT centered in the spring pack. The centering pin is set forward, therefore causing the axle to sit further forward and not center in the wheel opening. The later model springs can be used but you will need to relocate your spring hangers on the frame, basically move the fronts back further til your wheels are centered in the opening and then see where you need to hang the rears, depending on rear spring length. If you stay with the stock 68 rear springs in your 68, you shouldn't have much trouble getting most any other axle mounted under it, other than a possible pad relocation. You guys that know a lot more than me, feel free to chime in and let us know if there are major differences with the 73 up axles as far as mounting in our 67-72 trucks. __________________ 67 Short Fleet 4x4 04 Honda CRF450R 89 Toyota 4-Runner 34 Ford 2 door sedan - Long term project ---------------------------------------------- There is a very fine line between "hobby" and "mental illness"

09-08-2003, 09:07 PM	#4
darksaga Registered User Join Date: Nov 2002 Location: santa cruz cali Posts: 118	I get it now I took it that the centering pin was offset to the side not front to back, I was thinking why could I not just drill a new hole. Makes sense now __________________ 1968 gmc 3/4 4x4 longbed. built 469 700r4 (needs a th400 REAL SOON!), 14bolt ff rear 73 3/4 dana 44 1970 chevelle all wheel disc, tubular rear control arms tall spindle swap up front matching #'s 350 work in Progress

09-08-2003, 09:23 PM	#5
Pont I need another Barley Pop Join Date: Feb 2001 Location: Grants Pass, OR Posts: 1,629	I'm glad it makes sense to you because I got a headache reading my own post Just read Breeh's posts from now on and ignore mine. Breeh's the man and knows what he's talkin about. __________________ 67 Short Fleet 4x4 04 Honda CRF450R 89 Toyota 4-Runner 34 Ford 2 door sedan - Long term project ---------------------------------------------- There is a very fine line between "hobby" and "mental illness"

09-08-2003, 09:30 PM	#6
darksaga Registered User Join Date: Nov 2002 Location: santa cruz cali Posts: 118	I understood It fine, you wrote like I do at times (before editing) now on the front brothers list the front rear shackle as being the same from 67-72 but ord lists thier shackle kit to only work with 69+ I know the front fixed shackle is diffrent and I have a wtb in parts for sale for them right now would the only reason the ord kit would not work be becasue of the front bushing? their kit comes out to be cheaper then brothers and I would rather use the kit due to upgraded parts __________________ 1968 gmc 3/4 4x4 longbed. built 469 700r4 (needs a th400 REAL SOON!), 14bolt ff rear 73 3/4 dana 44 1970 chevelle all wheel disc, tubular rear control arms tall spindle swap up front matching #'s 350 work in Progress Last edited by darksaga; 09-09-2003 at 02:09 AM.

09-09-2003, 01:29 AM	#7
Pont I need another Barley Pop Join Date: Feb 2001 Location: Grants Pass, OR Posts: 1,629	I believe your right that the only difference up front is probably bushings. When I ordered my front springs, I ordered them for the 69-72 and they bolted right up to my 67. I believe that the 73+ will bolt in place as well. I'm not sure what the difference could be. I would just measure your fronts, and compare with what you want to replace and see if they will interchange. __________________ 67 Short Fleet 4x4 04 Honda CRF450R 89 Toyota 4-Runner 34 Ford 2 door sedan - Long term project ---------------------------------------------- There is a very fine line between "hobby" and "mental illness"

09-09-2003, 12:31 PM	#8
darksaga Registered User Join Date: Nov 2002 Location: santa cruz cali Posts: 118	breeh, pont thanks for the info more questions though iirc you are useing rancho 9000 shocks? they don't list an application for 67-68 did you use the one for 69-xx? __________________ 1968 gmc 3/4 4x4 longbed. built 469 700r4 (needs a th400 REAL SOON!), 14bolt ff rear 73 3/4 dana 44 1970 chevelle all wheel disc, tubular rear control arms tall spindle swap up front matching #'s 350 work in Progress Last edited by darksaga; 09-09-2003 at 12:35 PM.

09-09-2003, 08:16 PM	#9
Pont I need another Barley Pop Join Date: Feb 2001 Location: Grants Pass, OR Posts: 1,629	Yep, I used the 69-up shocks on my truck and they worked perfect, well almost perfect. The front shocks bolted right in and work great. The rears that I got (listed for an 8" lift) were about 2" short of mounting with them fully extended. Well that wasn't gonna work so I got into the Rancho catalog and found the longest shock they make with the correct ends that I needed. Returned the ones that were too short and ordered the long ones and they work great. I can honestly say that my truck rides better now than it did at stock height. __________________ 67 Short Fleet 4x4 04 Honda CRF450R 89 Toyota 4-Runner 34 Ford 2 door sedan - Long term project ---------------------------------------------- There is a very fine line between "hobby" and "mental illness"

09-09-2003, 08:32 PM	#10
darksaga Registered User Join Date: Nov 2002 Location: santa cruz cali Posts: 118	thanks for the info once I get the chevelle back on the road I will probably put a bigger lift on (it has a ~2.5" on it now). For now Im going to just replace the bushings, I found a place that had them in stock today and they should be here by tomarro I only plan on going with a 4" or so lift but even for that It looks like im going to need a longer driveshaft with the 2.5" the shaft is only in ~1/3 of the way __________________ 1968 gmc 3/4 4x4 longbed. built 469 700r4 (needs a th400 REAL SOON!), 14bolt ff rear 73 3/4 dana 44 1970 chevelle all wheel disc, tubular rear control arms tall spindle swap up front matching #'s 350 work in Progress

09-09-2003, 10:30 PM	#11
bigger=better Registered User Join Date: Sep 2003 Location: WV Posts: 92	spring swap Hey guys, Newbie here. ?I've been reading posts as research for my project and came across this one. thought I had what I needed now not so sure. I have a '68 4X4 suburban 1/2 ton and '75 3/4 ton axles (14 & 10 bolt) with springs, and th400 and TC (NP205?) that I want to swap in. Suggestions? Tips? Bad news? I am also swapping in a Mark VI 454. I am a capable mechanic just not familiar yet with old chevy 4X4s __________________ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ '68 GMC Sub 4X4 new project '69 Pontiac GTO 20 year project Never hold your farts in. They travel up your spine, into your brain, and that's where you get sh*tty ideas from.

09-09-2003, 11:19 PM	#12
darksaga Registered User Join Date: Nov 2002 Location: santa cruz cali Posts: 118	horde parts as for swaping a big block in mine was done before I bought it a few members here have done the swap, mine looks like it wasent that hard, the pass side framerail is ground out abit other then that the swap looked pretty easy. IIrc you need a 2wd big block engine crossmember anything will fit with a sawzall and a bfh happy building __________________ 1968 gmc 3/4 4x4 longbed. built 469 700r4 (needs a th400 REAL SOON!), 14bolt ff rear 73 3/4 dana 44 1970 chevelle all wheel disc, tubular rear control arms tall spindle swap up front matching #'s 350 work in Progress

09-10-2003, 08:51 PM	#13
Pont I need another Barley Pop Join Date: Feb 2001 Location: Grants Pass, OR Posts: 1,629	bigger=better, I don't see where you are going to have any problem using those 75 3/4ton axles but you might be SOL on the springs. Take the front springs and measure from eye to eye at the bushings. They might be the same length (check the width also along with the location of the spring centering pin) and you might be able to use the front springs. I can almost guarantee that the rear springs will be different in length and that the centering pin will be in the wrong location. You can use the 3/4ton rear springs but you will need to relocate the spring hangers to a different location on the frame. Both front and rear hangers! Hope this helps............ __________________ 67 Short Fleet 4x4 04 Honda CRF450R 89 Toyota 4-Runner 34 Ford 2 door sedan - Long term project ---------------------------------------------- There is a very fine line between "hobby" and "mental illness"

09-11-2003, 03:45 PM	#14
bigger=better Registered User Join Date: Sep 2003 Location: WV Posts: 92	Thanks, That is what I thot I was gonna get from what I read in the previous posts. Kinda wanted those heavier springs too. So I may try moving the hangers. __________________ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ '68 GMC Sub 4X4 new project '69 Pontiac GTO 20 year project Never hold your farts in. They travel up your spine, into your brain, and that's where you get sh*tty ideas from.

09-11-2003, 09:05 PM	#15
Pont I need another Barley Pop Join Date: Feb 2001 Location: Grants Pass, OR Posts: 1,629	Keep us posted on your progress. Good luck with your project. __________________ 67 Short Fleet 4x4 04 Honda CRF450R 89 Toyota 4-Runner 34 Ford 2 door sedan - Long term project ---------------------------------------------- There is a very fine line between "hobby" and "mental illness"



Register or Log In To remove these advertisements.

09-11-2003, 09:26 PM	#16
bigger=better Registered User Join Date: Sep 2003 Location: WV Posts: 92	OK, Maybe I'll post a pic or two tomorrow. __________________ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ '68 GMC Sub 4X4 new project '69 Pontiac GTO 20 year project Never hold your farts in. They travel up your spine, into your brain, and that's where you get sh*tty ideas from.

09-12-2003, 05:11 AM	#17
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	Those 1975 springs won't work on the 68 they will be about 3" too long in the front. For the rear you have the pin location and length of spring to look at could be 56" or 52" springs w/ the 1975 axles. __________________ 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

09-12-2003, 12:02 PM	#18
HeavyK20 Registered User Join Date: Dec 2001 Location: New Richmond, WI Posts: 547	Speaking of springs...has anyone noticed that there are 2 versions of the forward spring hanger on the rear axle of a K20? Version 1 has a small mount that does not hang below the frame rails. Version 2 has a large mount that is about 8 inches tall and hangs below the frame rail about 3 inches. There is a 2 inch differnce in the actual height of the spring bolt. Does anyone why there is a difference? __________________ Eric 1969 K20, 465/205 package

09-12-2003, 08:00 PM	#19
bigger=better Registered User Join Date: Sep 2003 Location: WV Posts: 92	Well here she is. Would you give $50 for her? Attached Images __________________ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ '68 GMC Sub 4X4 new project '69 Pontiac GTO 20 year project Never hold your farts in. They travel up your spine, into your brain, and that's where you get sh*tty ideas from.

09-12-2003, 08:02 PM	#20
bigger=better Registered User Join Date: Sep 2003 Location: WV Posts: 92	and again. Attached Images __________________ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ '68 GMC Sub 4X4 new project '69 Pontiac GTO 20 year project Never hold your farts in. They travel up your spine, into your brain, and that's where you get sh*tty ideas from.

09-12-2003, 08:43 PM	#21
Pont I need another Barley Pop Join Date: Feb 2001 Location: Grants Pass, OR Posts: 1,629	Oh yeh, I would give $50 for her several times over! __________________ 67 Short Fleet 4x4 04 Honda CRF450R 89 Toyota 4-Runner 34 Ford 2 door sedan - Long term project ---------------------------------------------- There is a very fine line between "hobby" and "mental illness"

09-13-2003, 08:37 AM	#22
bigger=better Registered User Join Date: Sep 2003 Location: WV Posts: 92	I am sure you don't need me to confirm it but you're right, these springs ain't gonna work. Yeah I gave $50 for her, and another $15 for a beat up 2wd L6 with no front clip that can just be seen in the background. __________________ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ '68 GMC Sub 4X4 new project '69 Pontiac GTO 20 year project Never hold your farts in. They travel up your spine, into your brain, and that's where you get sh*tty ideas from.

09-16-2003, 02:23 PM	#23
darksaga Registered User Join Date: Nov 2002 Location: santa cruz cali Posts: 118	I checked the part # from the front shocks I have now 5113 and the rancho app guide lists them as 67-72 2wd, 81-87 4wd, chevy luv 72-83 so I guess almost any shock would work the ones in there right now are so shot they don't rebound at all anymore but I never noticed the front springs are so stiff (stock with add-a-leaf) I never noticed. New springs here I come __________________ 1968 gmc 3/4 4x4 longbed. built 469 700r4 (needs a th400 REAL SOON!), 14bolt ff rear 73 3/4 dana 44 1970 chevelle all wheel disc, tubular rear control arms tall spindle swap up front matching #'s 350 work in Progress

07-02-2004, 09:04 PM	#25
bigger=better Registered User Join Date: Sep 2003 Location: WV Posts: 92	Progress Finally got the 3/4 ton axles under her! The front went in no sweat, had to move the spring perches in on the backend first time I ever moved perches, was easier than I thought. 454 is finished(basically), need new case for my th400 then I can move forward again. Unfortunately that will probably this time next year as I'm going to be gone the next several months happy to be this far at least __________________ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ '68 GMC Sub 4X4 new project '69 Pontiac GTO 20 year project Never hold your farts in. They travel up your spine, into your brain, and that's where you get sh*tty ideas from.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Register or Log In To remove these advertisements.