axle fitment - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mnick · 12-11-2003, 01:25 PM

does anyone know if you can bolt 73 axles into a 70 4x4 frame?
are they the same width at the spring perches and overall?
thanks in advance, Mike

**JIMs70GMC** · 12-11-2003, 02:42 PM

Front should bolt up, the rear also if 1/2 ton for sure.

**CUSTOM/10** · 12-11-2003, 04:24 PM

The front will bolt in, but I believe you'll find that you will have to relocate the spring purches and the shock mounts on the rear end. I put a set of differentails from a 76 in my 72 and thats what I had to do. Take some measurements ( center to center on your spring purches and shock mounts, I think there 40" for the springs and about 24" for the shocks and compare them to the 73 measurements.

Gary

GreenMystChevy · 12-11-2003, 08:14 PM

For my '75 3/4 ton axles, the front seems to fit right in but the rear has to have spring perches and shock mounts relocated. I'm pretty sure after '72 that's the way it is.

DaHateTank · 12-12-2003, 04:46 AM

Front is the same.

Rear:

1/2 ton and 3/4 ton 73-87 have wider spring perches than '68-'72

1-ton '73-87 reputedly have same spring perch width as '68-'72. The frame mounts for rear springs ARE different on later model 1 tons.

So...if you have a '73 one ton 4WD ( Im jealous ) then axles are a bolt in. If you have a 1/2 ton or 3/4 ton, the only front axle is a direct bolt-in.

If you are talking about axle shafts, you're opening a can of worms.

-M

Scrub · 12-13-2003, 12:38 PM

Re: rear axles
1 ton duals might be the same, but a 73 to 87 Corp 14 will need to have the perches and shock mounts moved. There are a couple styles of perch mounts. some are stamped steel and pretty easy to cut off, others are cast steel and (stronger) harder to get off. I have mine air-arced off at a local welding shop. Some board members wack them off with a plasma. Being older than dirt itself, I have never seen a plasma used like that, so make your own choice, but I would not recomend trying to cut the cast type off with an actylene torch. I have a pic of mine in the thread entitled "Which is the front of the springs"

A 73 to 87 Corp 14 will bolt right in to a 2wd.

If you can find a corp 14, I sure recomend them. I have been running them for over 20 years on my 70 pickup and have hard great luck.

Good luck to you

Beast388 · 12-13-2003, 01:31 PM

I have '77 3/4 ton axles under my '71 Suburban.

The front axle is 100% bolt in.

As others have said the rear will need some modification.

67-72 4X4's have a center to center spring perch spacing of 40"

73-87(91) 1/2 & 3/4 - 2wd's & 4wd's have a spacing of 42.5"

73-87 2wd 1 tons have a spacing of 40.5"

77-87 4wd 1 tons have a spacing of 40.5"

There were no 1 ton 4wd's until 1977.

Scrub · 12-13-2003, 02:58 PM

That's good information.
What years did the Corp 14 come in?
I think it came in both a 1-ton and 3/4 ton truck. I remember that my buddy bought a new 74 3/4 ton and it had a Corp 14 (I think)

DaHateTank · 12-14-2003, 03:12 AM

Quote:

Originally posted by Beast388
...There were no 1 ton 4wd's until 1977...

Crap, I knew that

Had my head up my butt when I typed that '73 one ton 4WD BS...

I know alot of people have gotten away with using the 40-1/2" one ton 14Bs on 68-72s...

Much like people put dodge D60 fronts in Chevy trucks (IIRC the springs are an inch farther apart in the Dodges)

-M

Beast388 · 12-15-2003, 01:37 AM

Quote:

Originally posted by Scrub
That's good information.
What years did the Corp 14 come in?
I think it came in both a 1-ton and 3/4 ton truck. I remember that my buddy bought a new 74 3/4 ton and it had a Corp 14 (I think)

The Corp. 14 bolt full-floater is a 73-up axle. It was used in 3/4 & 1 tons, but not every 3/4 & 1 ton. In the early 80's, the 9.5" 14 bolt semi-floater was used in some 3/4 tons as well. Dually trucks could get either the 14BFF or a Dana 70.

12-11-2003, 01:25 PM	#1
mnick Registered User Join Date: Jan 2001 Location: xenia,ohio,45385 Posts: 73	axle fitment does anyone know if you can bolt 73 axles into a 70 4x4 frame? are they the same width at the spring perches and overall? thanks in advance, Mike

12-11-2003, 02:42 PM	#2
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	Front should bolt up, the rear also if 1/2 ton for sure. __________________ 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

12-11-2003, 08:14 PM	#4
GreenMystChevy Registered User Join Date: Jan 2002 Location: Woodinville, WA Posts: 513	For my '75 3/4 ton axles, the front seems to fit right in but the rear has to have spring perches and shock mounts relocated. I'm pretty sure after '72 that's the way it is. __________________ Jeremy '71 C-10 '72 GMC K2500 '72 Nova (Dad's) '70 Chevelle SS '55 Sedan Delivery Attempting to build up this here 4x4...make her real tall and purty...well, maybe just tall

12-13-2003, 12:38 PM	#6
Scrub Collector of rusty Items Join Date: Dec 2001 Location: Sisters,Oregon USA Posts: 731	Re: rear axles 1 ton duals might be the same, but a 73 to 87 Corp 14 will need to have the perches and shock mounts moved. There are a couple styles of perch mounts. some are stamped steel and pretty easy to cut off, others are cast steel and (stronger) harder to get off. I have mine air-arced off at a local welding shop. Some board members wack them off with a plasma. Being older than dirt itself, I have never seen a plasma used like that, so make your own choice, but I would not recomend trying to cut the cast type off with an actylene torch. I have a pic of mine in the thread entitled "Which is the front of the springs" A 73 to 87 Corp 14 will bolt right in to a 2wd. If you can find a corp 14, I sure recomend them. I have been running them for over 20 years on my 70 pickup and have hard great luck. Good luck to you __________________ Scrub Sisters, Oregon - Home of the Sisters Rodeo. 70 GMC 1,000,000 + miles 72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.

12-13-2003, 01:31 PM	#7
Beast388 Suburbans RULE! Join Date: Jan 2000 Location: Clinton, IA 52732 Posts: 689	I have '77 3/4 ton axles under my '71 Suburban. The front axle is 100% bolt in. As others have said the rear will need some modification. 67-72 4X4's have a center to center spring perch spacing of 40" 73-87(91) 1/2 & 3/4 - 2wd's & 4wd's have a spacing of 42.5" 73-87 2wd 1 tons have a spacing of 40.5" 77-87 4wd 1 tons have a spacing of 40.5" There were no 1 ton 4wd's until 1977. __________________ --Ben 71 GMC Suburban 4X4 The "Beast" 388 CID Stroker, TH350, NP205, 8-lug D44, 14BFF w/ Detroit, 4.10:1 gears, 4-Wheel Disks 4" Lift, 35" MT/R's.

12-11-2003, 04:24 PM	#3
CUSTOM/10 Senior Member Join Date: May 2003 Location: Sandown, NH Posts: 2,857	The front will bolt in, but I believe you'll find that you will have to relocate the spring purches and the shock mounts on the rear end. I put a set of differentails from a 76 in my 72 and thats what I had to do. Take some measurements ( center to center on your spring purches and shock mounts, I think there 40" for the springs and about 24" for the shocks and compare them to the 73 measurements. Gary

12-12-2003, 04:46 AM	#5
DaHateTank Registered User Join Date: Aug 2002 Location: Iowa Posts: 119	Front is the same. Rear: 1/2 ton and 3/4 ton 73-87 have wider spring perches than '68-'72 1-ton '73-87 reputedly have same spring perch width as '68-'72. The frame mounts for rear springs ARE different on later model 1 tons. So...if you have a '73 one ton 4WD ( Im jealous ) then axles are a bolt in. If you have a 1/2 ton or 3/4 ton, the only front axle is a direct bolt-in. If you are talking about axle shafts, you're opening a can of worms. -M

12-13-2003, 02:58 PM	#8
Scrub Collector of rusty Items Join Date: Dec 2001 Location: Sisters,Oregon USA Posts: 731	That's good information. What years did the Corp 14 come in? I think it came in both a 1-ton and 3/4 ton truck. I remember that my buddy bought a new 74 3/4 ton and it had a Corp 14 (I think) __________________ Scrub Sisters, Oregon - Home of the Sisters Rodeo. 70 GMC 1,000,000 + miles 72 K-20 project, 456 Dana60 front, Corp14 rear w/locker, 265R19.5 tires 20-ply. Warn 12k winches both ends, Cross-over steering with raised tie-rod, Powerbox steering, 4500 watt 120-AC power, Air, Hydraulic aux power, 4 inch lift, 5000 lb air-bags both ends.



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