1/2 ton swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Scrubby · 04-04-2005, 04:30 PM

I have a '71 3/4 ton big block suburban. I also have a '72 1/2 ton parts truck. I have been kicking around the idea of swapping the suburban to 1/2 ton to get a better ride, more lowering options, and more wheel options.

The back, I believe, is just swapping the axle for the 5 lug one. But, I am not sure how far to go in the front. I was wondering if you can swap the a-arms and everything out? Or do you need to change the crossmember? What is the easiest? Anyone got any experience here?

I'm probably going to be rebuilding the whole front as I go with new bushings, ends, etc. So, keeping that all together is not a big deal since I will probably tear it apart anyway. Then there is probably drop spindles, and lowering springs in my future...

JimKshortstep4x4 · 04-04-2005, 08:14 PM

I would change the crossmember. They are not that hard to remove and the 3/4 upper and lower control arm shafts are different. The special bolts that hold the upper a arm shafts are also different.

There may be a way to use the 3/4 ton parts but it looks like it could become tricky.

I see that you have one of those "rare" three door Burbs, very nice!

Jim

RicksTrucks · 04-04-2005, 08:17 PM

Is the current rear coil or spring? I have been told that the springs on the GMC ride a little nicer than the Chevy coils. Maybe move it to a 3/4 GMC long frame. Or are the frames for the burbs different than the longbeds?

Scrubby · 04-04-2005, 08:50 PM

It is coil in the rear.

I think that the burb and truck frames are different in where the body mounts are, but I could be wrong.

**Palf70Step** · 04-04-2005, 09:38 PM

Yes burb and truck frames are different.
Swap your rear axle assembly over....and as was mentioned swap the whole cross member assembly to get the 1/2 ton springs and spindles. too many different parts between 3/4 and 1/2 ton. It may sound dumb, but the only thing I am not sure about would be your driveshaft. I don't know if the u-joints are the same between the two rear axles.

You may also have the option of just swapping springs. I've put 3/4 tone springs on 1/2 tons, I don't see why the process could not be reverse. Probably the simpler of the options, unless you want the 5 lug wheel options.

BTW Very nice looking burb.

ElGracho · 04-06-2005, 08:07 PM

I thought the crossmembers were all the same. I think just the cross shafts, and arms out are different between a 1/2 and 3/4 tons?

**Palf70Step** · 04-06-2005, 08:25 PM

True, but taking it as one piece is simpler (to me anyways) than a hundred little pieces

69 longhorn · 04-06-2005, 09:13 PM

If you are rebuilding the front suspension, pcs are no issue. You can use the top a arms from the 3/4 ton,the 1/2 ton balljionts will bolt in. just be sure to use the 3/4 ton shafts & screws with them. no need to swap the crossmember either, but you will swap all the rest of the pcs, from the lower a arms, to balljoints, spindles, & all the steering linkage.....been there, & done that..........69L

04-04-2005, 04:30 PM	#1
Scrubby Check out GMTrucks.org Join Date: Sep 2003 Location: Boise, Id Posts: 284	1/2 ton swap I have a '71 3/4 ton big block suburban. I also have a '72 1/2 ton parts truck. I have been kicking around the idea of swapping the suburban to 1/2 ton to get a better ride, more lowering options, and more wheel options. The back, I believe, is just swapping the axle for the 5 lug one. But, I am not sure how far to go in the front. I was wondering if you can swap the a-arms and everything out? Or do you need to change the crossmember? What is the easiest? Anyone got any experience here? I'm probably going to be rebuilding the whole front as I go with new bushings, ends, etc. So, keeping that all together is not a big deal since I will probably tear it apart anyway. Then there is probably drop spindles, and lowering springs in my future... Last edited by Scrubby; 04-04-2005 at 04:31 PM.

04-04-2005, 08:14 PM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	I would change the crossmember. They are not that hard to remove and the 3/4 upper and lower control arm shafts are different. The special bolts that hold the upper a arm shafts are also different. There may be a way to use the 3/4 ton parts but it looks like it could become tricky. I see that you have one of those "rare" three door Burbs, very nice! Jim Last edited by JimKshortstep4x4; 04-04-2005 at 08:16 PM.

04-04-2005, 08:17 PM	#3
RicksTrucks Senior Member Join Date: Jan 2005 Location: Claremore, OK 74017 Posts: 2,640	Is the current rear coil or spring? I have been told that the springs on the GMC ride a little nicer than the Chevy coils. Maybe move it to a 3/4 GMC long frame. Or are the frames for the burbs different than the longbeds? __________________ 68 Short Stepside C-10 69 SWB C-10 70 Flatbed C-20 70 LWB C-20 BB402 70 LWB C-10 CST 70 LWB C-10 CST 71 Short Stepside Cheyenne C-10 72 LWB C-10 72 Blazer 4x4 4spd 95 Jeep Cherokee 4x4 Last edited by RicksTrucks; 04-04-2005 at 08:18 PM.

04-04-2005, 09:38 PM	#5
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 46,820	Yes burb and truck frames are different. Swap your rear axle assembly over....and as was mentioned swap the whole cross member assembly to get the 1/2 ton springs and spindles. too many different parts between 3/4 and 1/2 ton. It may sound dumb, but the only thing I am not sure about would be your driveshaft. I don't know if the u-joints are the same between the two rear axles. You may also have the option of just swapping springs. I've put 3/4 tone springs on 1/2 tons, I don't see why the process could not be reverse. Probably the simpler of the options, unless you want the 5 lug wheel options. BTW Very nice looking burb. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God! Last edited by Palf70Step; 04-04-2005 at 09:41 PM.

04-06-2005, 08:07 PM	#6
ElGracho Gentleman Jim Driver Join Date: Nov 2002 Location: Poulsbo, WA Posts: 1,550	I thought the crossmembers were all the same. I think just the cross shafts, and arms out are different between a 1/2 and 3/4 tons? __________________ Joe '75 GMC Gentleman Jim '84 Chev C10 Short Wide - Super duper plain (manual steering, manual brakes, no dome light, no cig lighter) '85 Chev C10 Short Wide - Super plain Vortec 4.8 4L60E trans also: '81 K30, '83 C30 Crew Dually, '84 M1028 CUCV, '85 M1009 CUCV, another '85 C10 SWB, '89 R3500 Flatbed

04-04-2005, 08:50 PM	#4
Scrubby Check out GMTrucks.org Join Date: Sep 2003 Location: Boise, Id Posts: 284	It is coil in the rear. I think that the burb and truck frames are different in where the body mounts are, but I could be wrong.

04-06-2005, 08:25 PM	#7
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 46,820	True, but taking it as one piece is simpler (to me anyways) than a hundred little pieces __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!

04-06-2005, 09:13 PM	#8
69 longhorn Registered User Join Date: Aug 2001 Location: rock island,il,usa Posts: 5,382	If you are rebuilding the front suspension, pcs are no issue. You can use the top a arms from the 3/4 ton,the 1/2 ton balljionts will bolt in. just be sure to use the 3/4 ton shafts & screws with them. no need to swap the crossmember either, but you will swap all the rest of the pcs, from the lower a arms, to balljoints, spindles, & all the steering linkage.....been there, & done that..........69L __________________ http://community.webshots.com/user/hotrodhorn



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