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Lifted? How high can you go?

7

78 GMC Jimmy

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How high can you lift a late 70's K5?

At what point do you lose your highway capability?

What is the maximum reasonable lift for a late 70's K5 before it is not longer reasonable/safe to use on the freeway?

Body lift? Suspension lift? What are the limits of each/combined?
 
Anything over 6 is too stiff to be usable in my opinion. Others may not agree.
Also beyond that driveline angles start getting real sketchy and hard to make right
 
You can do 6, and a 3" body lift if you really like tall trucks. But personally I never recommend 3" body lifts, just because I was raised to dislike em lol.

There are ways to make the driveline work also. But I haven't done it, so others would have to explain that.
I know there's different yokes and such that offer more flex before bind, etc.
 
I assume you are asking about replacement leaf springs. Any lift of this type will decrease highway capability, all other things being unchanged. You can certainly mitigate the impact of a “normal” lift. Personally, I wouldn’t go higher than a 6” suspension lift and a 1” body lift. Others may disagree, but that’s my opinion given your question.
 
It all depends on how big of tire you can run and how much money you have. Legally for street use, your headlights need to be with in x amount of inches from the ground varies by state.
 
Also makes a difference if you swap out to coilovers and a linked suspension. I think you can do more than six then, but it's going to be expensive. And, as was mentioned, probably illegal. Certainly in CA. I wouldn't put more than an inch of body lift if you're doing a suspension lift also. I wouldn't do more than an inch of body lift, period.
 
What are you going to be doing with the truck, they make a 12" lift spring, plus a 3 inch body. It won't ride decent, or handle well but you could clear 44's and help send your driveshaft builder's kids to a good school.

Reasonably 6 inches clears big tires with a little trimming and rides okay.

Better yet in my experience is a 4 inch spring, one inch "zero rate" and one inch body lift to make it ride good and have clearance.
 
Wes Harden said:
It all depends on how big of tire you can run and how much money you have. Legally for street use, your headlights need to be with in x amount of inches from the ground varies by state.
Click to expand...

Hmm. I had not considered the legality of it. I suppose that would need to be taken into consideration.
 
yeah I bet that was one hell of ticket. Has Kommiefornia plates. Biggest tire street tire in Ca is 40". IIRC the head lamp height in Ca is something like 37" for a half ton, or was when this picture taken. Then there is the whole lift blocks on the front axle thing. Wasn't aware of u bolt direction ordinance.
 
My gmt400 has U bolts threads down. So did my square dually I believe.
Both rwd though.
 
anwat said:
I think one of the major automakers did backwards u-bolts for a bit. Ford and maybe Toyota?
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It's fairly common. Ford and Dodge even did factory lift blocks that way. They should give tickets for that and also building your truck so it can't run a front driveshaft and/or having Carolina squat.
 
78 GMC Jimmy said:
How high can you lift a late 70's K5?

At what point do you lose your highway capability?

What is the maximum reasonable lift for a late 70's K5 before it is not longer reasonable/safe to use on the freeway?

Body lift? Suspension lift? What are the limits of each/combined?
Click to expand...

I used to have a K5 with with 8" Skyjacker lift and 3" body lift on 39.5 TSL Swampers. used to drive it all over DFW with no problems. 76 K10 short bed with 8 and 3 and drove it all over Colorado Springs when I was in the Army there. 84 K10 long bed with 8 and 3 again on 39" boggers. Did they ride rougher than my car? sure, but you have to know what you have and drive it accordingly. I drove an 88 K5 from Virginia Beach to Fort Worth with a 4" lift and 3" body lift on 35s. long distance and had no problems.
another thing you need to consider is once you lift it and put big tires on it, depending on the gearing it will be dog. I had a 74 K10 with a 6" lift and 36" Swampers with 3.07s in high school and right after. I lived 7 miles out in the country. I would drive to town in high range and once in town put it in low range so I would be able to get out of people's way.
to do a big lift correctly there are lots of variables involved: new gearing, driveshafts, brake lines, steering, it takes longer to slow down big tires which is more brake maintenance, accelerated component wear; and probably more that I can't think of right now.

1712950776626.png
 
fourwheelerjeff said:
I used to have a K5 with with 8" Skyjacker lift and 3" body lift on 39.5 TSL Swampers. used to drive it all over DFW with no problems. 76 K10 short bed with 8 and 3 and drove it all over Colorado Springs when I was in the Army there. 84 K10 long bed with 8 and 3 again on 39" boggers. Did they ride rougher than my car? sure, but you have to know what you have and drive it accordingly. I drove an 88 K5 from Virginia Beach to Fort Worth with a 4" lift and 3" body lift on 35s. long distance and had no problems.
another thing you need to consider is once you lift it and put big tires on it, depending on the gearing it will be dog. I had a 74 K10 with a 6" lift and 36" Swampers with 3.07s in high school and right after. I lived 7 miles out in the country. I would drive to town in high range and once in town put it in low range so I would be able to get out of people's way.
to do a big lift correctly there are lots of variables involved: new gearing, driveshafts, brake lines, steering, it takes longer to slow down big tires which is more brake maintenance, accelerated component wear; and probably more that I can't think of right now.

View attachment 472369
Click to expand...
Even your cartoon has lift blocks in the front, not to mention shackles in the front of the front springs. :cry:
 
A ticket / ordinance for u-bolts facing down?? You guys do realize that quite a few square body 1 tons were built that way? I think all 1 ton squares had downward u-bolts, if I'm wrong then at least all 2wd duallies did because that's how the sway bar attaches. :screwy:
 
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