Need Help! ? for 3/4 ton 6" lift - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ALBATROSS · 12-14-2004, 10:04 PM

Ok guys I need your help, I've got a 71 gmc short half ton with a 6 in lift blocks in the rear. I broke one of the rear springs, and I had a set of 3/4 springs of a 71 or 72. I bought some 4in blocks for the 3/4 springs but now the truck looks like a stink bug. My question is for those who have 3/4 ton with a 6 in lift with blocks what size blocks do you have? When I ordered mine, the guy at suspension conn. wasn't real sure which ones I needed. I'm thinking a 2in but I want to make sure before I order another set. Any help would be greatly appreaciated.

Thanks, Albie

Budweis · 12-15-2004, 04:06 AM

nobody uses blocks anymore do they? lol seriously id go for springs and do away with blocks but if have to have why cant you just measure from fenders and subtract it from where 4" blocks put you at? not sure i understand.

**JIMs70GMC** · 12-15-2004, 07:24 AM

Sounds like you could just add an extra leaf to the pack. Is it stiff in the rear now? You could get a long add-a-leaf vice a short thick one. That's what I did on my 70 to get an extra inch an a half of lift in the rear. You want to keep your blocks as short as possible to minimize drive line bind during acceleration/take off. That could be what broke your spring to begin with.

ALBATROSS · 12-15-2004, 01:13 PM

budwies,
Yeah, I can't afford springs right now

jims70gmc,

My problem is that I have too much lift now. And I don't want to remove any leafs because I need the strength. Thats why my 1/2ton spring broke, I overloaded it. I would rather have lift springs, but it looks like I'm not going to have to go with a very big block. I guess I could just order the 2in. blocks and if its too short add another leaf.

Mudder · 12-15-2004, 02:35 PM

There's nothing wrong with blocks in the rear up to 6 inches. Someone give me a link to somewhere thats says its not good. You can use 4 inch blocks and keep the same ride quality as the original springs. Blocks on the front are a no-no and very dangerous. Twenty years ago adding lift springs in the rear was unheard of unlesss you had someone close that could make them.

Budweis · 12-15-2004, 05:33 PM

yeah i dont think anyone said blocks were dangerous, from what i was told by everybody before i bought mine was that it ruins ride quality and articulation. so thats what i meant mudder and also yes its ok to have a 1" block(aka zero rate) on the front if its the kind that bolts to spring pack. albatross like i said earlier should be able to measure and figure what size block need as if got a 4" now and want truck 1 inch lower get a 3 etc. i believe somone makes a 3 1/2" one that ive seen.

**JIMs70GMC** · 12-15-2004, 07:51 PM

I wasn't saying lift blocks were bad but, the extra leverage on the springs caused by the blocks cause there to be more "spring wrap" then with smaller blocks. This is compounded with big tires. It's the u-joint that suffers more. Of course ladder bars and traction bars can help. I have 4" blocks on my 71 and before I put the bed on I did some burn outs and the pinion rotated up almost 45 degrees. I plan on fabbing some traction bars myself(might check out blackbirds also).
Question at hand:
I don't understand too much lift but you want a bigger block?????? I 've seen 3" blocks as well as 2.5" blocks. Just need to check around.

4x4Poet · 12-16-2004, 01:24 AM

If you must use blocks, place a bottle jack under each installed 3/4 ton spring with the u-bolts uninstalled. Position the jack heads near the spring pearch behind the axle. Raise truck equally on both sides simultaneously until at desired height. Use safety stands under frame. Then measure distance from pearch to axle to determine block height. Be sure to note any wrap of the spring to check for distorted measurements. This works best when the springs are C-clamped fore and aft of the pearch.

Can you bring the front down to be level, or just below, the rear as it sits now?

If you haven't finished paint or have qualms about trimming fenders, a safer COG can be achieved by trimming the bottoms of the fenders to clear the large tires without needing as much lift. The lower front fender is most likely to interfere with large tires under a mild lift.

And BTW, a Californian wheeler should not have a redneck lift at the rear axle. No offense against rednecks.

ALBATROSS · 12-16-2004, 11:03 PM

Thanks for your guys' input. I think some of you got a little confused, with the 4 inch blocks and the 3/4 springs the rear is too high. Anyway I ordered some 2 inch blocks and I think they should work. I think the 3 inch would also be too high. Will lift springs still handle heavy loads? What about soft ride lift springs?

12-14-2004, 10:04 PM	#1
ALBATROSS Registered User Join Date: Feb 2004 Location: Redway,Ca Posts: 30	Need Help! ? for 3/4 ton 6" lift Ok guys I need your help, I've got a 71 gmc short half ton with a 6 in lift blocks in the rear. I broke one of the rear springs, and I had a set of 3/4 springs of a 71 or 72. I bought some 4in blocks for the 3/4 springs but now the truck looks like a stink bug. My question is for those who have 3/4 ton with a 6 in lift with blocks what size blocks do you have? When I ordered mine, the guy at suspension conn. wasn't real sure which ones I needed. I'm thinking a 2in but I want to make sure before I order another set. Any help would be greatly appreaciated. Thanks, Albie

12-15-2004, 04:06 AM	#2
Budweis Geared for Collision Join Date: Jan 2004 Location: St. Louis, Mo. Posts: 683	nobody uses blocks anymore do they? lol seriously id go for springs and do away with blocks but if have to have why cant you just measure from fenders and subtract it from where 4" blocks put you at? not sure i understand. __________________ MEMBER OF THE 4 WHEEL DISK BRAKE CLUB 1970 C/K20 3/4 Ton 1996 Collectors Edition Corvette 1977 Corvette Coupe

12-15-2004, 07:24 AM	#3
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	Sounds like you could just add an extra leaf to the pack. Is it stiff in the rear now? You could get a long add-a-leaf vice a short thick one. That's what I did on my 70 to get an extra inch an a half of lift in the rear. You want to keep your blocks as short as possible to minimize drive line bind during acceleration/take off. That could be what broke your spring to begin with. __________________ 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

12-15-2004, 02:35 PM	#5
Mudder Registered User Join Date: Feb 2001 Location: East Central, MO Posts: 11,336	There's nothing wrong with blocks in the rear up to 6 inches. Someone give me a link to somewhere thats says its not good. You can use 4 inch blocks and keep the same ride quality as the original springs. Blocks on the front are a no-no and very dangerous. Twenty years ago adding lift springs in the rear was unheard of unlesss you had someone close that could make them. Last edited by Mudder; 12-15-2004 at 02:37 PM.

12-15-2004, 05:33 PM	#6
Budweis Geared for Collision Join Date: Jan 2004 Location: St. Louis, Mo. Posts: 683	yeah i dont think anyone said blocks were dangerous, from what i was told by everybody before i bought mine was that it ruins ride quality and articulation. so thats what i meant mudder and also yes its ok to have a 1" block(aka zero rate) on the front if its the kind that bolts to spring pack. albatross like i said earlier should be able to measure and figure what size block need as if got a 4" now and want truck 1 inch lower get a 3 etc. i believe somone makes a 3 1/2" one that ive seen. __________________ MEMBER OF THE 4 WHEEL DISK BRAKE CLUB 1970 C/K20 3/4 Ton 1996 Collectors Edition Corvette 1977 Corvette Coupe Last edited by Budweis; 12-15-2004 at 05:35 PM.

12-15-2004, 01:13 PM	#4
ALBATROSS Registered User Join Date: Feb 2004 Location: Redway,Ca Posts: 30	budwies, Yeah, I can't afford springs right now jims70gmc, My problem is that I have too much lift now. And I don't want to remove any leafs because I need the strength. Thats why my 1/2ton spring broke, I overloaded it. I would rather have lift springs, but it looks like I'm not going to have to go with a very big block. I guess I could just order the 2in. blocks and if its too short add another leaf.

12-15-2004, 07:51 PM	#7
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	I wasn't saying lift blocks were bad but, the extra leverage on the springs caused by the blocks cause there to be more "spring wrap" then with smaller blocks. This is compounded with big tires. It's the u-joint that suffers more. Of course ladder bars and traction bars can help. I have 4" blocks on my 71 and before I put the bed on I did some burn outs and the pinion rotated up almost 45 degrees. I plan on fabbing some traction bars myself(might check out blackbirds also). Question at hand: I don't understand too much lift but you want a bigger block?????? I 've seen 3" blocks as well as 2.5" blocks. Just need to check around. __________________ 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

12-16-2004, 01:24 AM	#8
4x4Poet Registered User Join Date: Nov 2004 Location: "Under Montana skies." Posts: 1,836	If you must use blocks, place a bottle jack under each installed 3/4 ton spring with the u-bolts uninstalled. Position the jack heads near the spring pearch behind the axle. Raise truck equally on both sides simultaneously until at desired height. Use safety stands under frame. Then measure distance from pearch to axle to determine block height. Be sure to note any wrap of the spring to check for distorted measurements. This works best when the springs are C-clamped fore and aft of the pearch. Can you bring the front down to be level, or just below, the rear as it sits now? If you haven't finished paint or have qualms about trimming fenders, a safer COG can be achieved by trimming the bottoms of the fenders to clear the large tires without needing as much lift. The lower front fender is most likely to interfere with large tires under a mild lift. And BTW, a Californian wheeler should not have a redneck lift at the rear axle. No offense against rednecks. __________________ '71 GMC K20 Suburban, '71 GMC K10 Suburban, '72 Chevy C10 CST Suburban, '72 Chevy K20 clunker pickup.

12-16-2004, 11:03 PM	#9
ALBATROSS Registered User Join Date: Feb 2004 Location: Redway,Ca Posts: 30	Thanks for your guys' input. I think some of you got a little confused, with the 4 inch blocks and the 3/4 springs the rear is too high. Anyway I ordered some 2 inch blocks and I think they should work. I think the 3 inch would also be too high. Will lift springs still handle heavy loads? What about soft ride lift springs?



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