Author Topic: Leaf spring  (Read 1085 times)

Offline chevydave112689

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Leaf spring
« on: July 31, 2022, 03:16:12 AM »
1987 gmc k25 ( was told it's a k25 heavy. Not sure if that's a thing)
5.7L long tube headers
Nv3500 5 speed swap
Dana 44 front/ 14 bolt rear
So I recently bought a set of add-a-leafs that were supposed to be for my front axel however the factory springs have zero positive lift. The new leafs have crazy positive arch. Can I safely compress that to the factory flat leaf pack. My next question will I see any lift from it. I'll try and post back with the Amazon link. I  can't afford a traditional lift kit and need to be able to clear 35 in tires. Will I need to make any steering adjustments? I think it's a great time to mention I'll be changing all the bushings with polyurethane. I'll also be changing all 4 ball joints and the u joints in the front axel. Also the original vin tag is missing as well as rpo codes. Can I find my axel ratio with out pulling the diff cover. I've read theirs a code stamped to the axel I have the first 3 as follows KJM. I want disc brakes in the rear. I don't think I'll need the strength of the 14 bolt but don't know what I have for options.

Offline VileZambonie

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Re: Leaf spring
« Reply #1 on: July 31, 2022, 06:22:24 PM »
If your truck is one of these trucks, then no it is not a K25, it would be a V2500. Heavy meaning it would need to eat fewer carbs I guess. There is no such thing as a heavy. Also, an axel is really an axle, yes spelling counts. I'm having a hard time understanding what you are asking about your springs. What is zero positive and crazy positive? You need to post some pictures of what you are talking about. You can ballpark your gear ratio, however, it is a good idea to pull the cover and inspect as well as change your fluid in there if you are unfamiliar with the truck.

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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Mr Diesel

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Re: Leaf spring
« Reply #2 on: July 31, 2022, 08:26:11 PM »
Probably would help a little if you narrowed down your questions or organized them a little better.

Do a forum or DuckDuckGo search for details about finding you rear end tag or ratio. Lots of detailed answers.

It sounds like you might have ordered the wrong front springs, but more detail or pictures would help.

No idea if it will lift your truck. Anything there is speculation. Install the right springs and find out!
1976 C20 Crewcab, 6.2L/SM465
1982 K30 Crewcab , 427TD/TH400
1983 C30, 6.2L/TH400
1983 K30 Crewcab 454/700R4
1986 K10 350/400. 1989 K30 cab/chassis 454/SM465