Lowering 1981 c20

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

ajwic1

Junior Member
Joined
Mar 3, 2024
Posts
11
Reaction score
3
Location
Nelson, BC, Canada
First Name
Alex
Truck Year
1981
Truck Model
c2500
Engine Size
5.7L v8 (350)
Hi there, I have a 1981 c20 and im looking to lower it 4/6 or 5/5 in that ballpark. would i be correct in saying that a flip kit gets you 8 inches not 6?

I've really struggled to find kits and lowering parts for this truck tbh. Any advice on how to achieve my goal is welcomed.
 

Grit dog

Full Access Member
Joined
May 18, 2020
Posts
6,963
Reaction score
12,211
Location
Auburn, Washington
First Name
Todd
Truck Year
1986, 1977
Truck Model
K20, C10
Engine Size
454, 350
If you add it up, just look at your suspension now and add the thickness of the springs, the perch and the axle and that’s how much it will lower it. About 6-6.5”.
As far as lowering kits and parts, they are plentiful, anything you might need.
 

84GMCSierra

Full Access Member
Joined
Feb 26, 2023
Posts
366
Reaction score
434
Location
Central Arizona
First Name
Paul
Truck Year
1984
Truck Model
C2500
Engine Size
350
Hi there, I have a 1981 c20 and im looking to lower it 4/6 or 5/5 in that ballpark. would i be correct in saying that a flip kit gets you 8 inches not 6?

I've really struggled to find kits and lowering parts for this truck tbh. Any advice on how to achieve my goal is welcomed.
If and when you lower your truck, please post pics. I want to do that with my 84 C2500, but not so low. Maybe just a couple inches.
 

mlsceo

Full Access Member
Joined
Dec 29, 2022
Posts
392
Reaction score
1,172
Location
Kingsburg California
First Name
Manuel
Truck Year
1977
Truck Model
c10
Engine Size
350
These guys only show 2020-2023 years for GMC. In Chevy, they only go back to 1988

You're partly correct. They go to 88 for GMC. For Chevy they go back as far as 1970 for axle flip kits. For drop spindles etc, they go to 71. I had to look back at the OP's avatar again to notice that he's working on a c2500 not a c20. His post reads c20, his avatar reads c2500. Which is it? On the other hand, wouldn't a shackle or drop spring be the same for an 81 c20 and an 81 c2500? Does one use coil springs and the other leaf springs? Maybe some more knowledgeable members can weigh in on that.
 
Last edited:

mlsceo

Full Access Member
Joined
Dec 29, 2022
Posts
392
Reaction score
1,172
Location
Kingsburg California
First Name
Manuel
Truck Year
1977
Truck Model
c10
Engine Size
350
If and when you lower your truck, please post pics. I want to do that with my 84 C2500, but not so low. Maybe just a couple inches.
Chassis Tech Suspension on Ebay shows 2" drop springs and shackles to fit c20, c2500. I would contact them to confirm fit though.
 
Last edited:

mlsceo

Full Access Member
Joined
Dec 29, 2022
Posts
392
Reaction score
1,172
Location
Kingsburg California
First Name
Manuel
Truck Year
1977
Truck Model
c10
Engine Size
350
Hi there, I have a 1981 c20 and im looking to lower it 4/6 or 5/5 in that ballpark. would i be correct in saying that a flip kit gets you 8 inches not 6?

I've really struggled to find kits and lowering parts for this truck tbh. Any advice on how to achieve my goal is welcomed.
Chassis Tech Suspension shows a 6/8 kit to fit your c2500. (the listing reads 6/6 AND 6/8??) Apparently there are two styles of calipers to deal with, bolt on or clip on. You'll want to check which ones you have, then contact them for fitment. They also show individual parts that will hopefully get you closer to the 5/5 you mentioned.
 
Last edited:

tboltkc

Junior Member
Joined
Jan 14, 2022
Posts
2
Reaction score
4
Location
KC, MO area
First Name
Travis
Truck Year
1985
Truck Model
C20 3+3
Engine Size
6.0L
Switch has 3/4 and 6/8 for 73-91 C20 & C30. Is GMC different?
 

mlsceo

Full Access Member
Joined
Dec 29, 2022
Posts
392
Reaction score
1,172
Location
Kingsburg California
First Name
Manuel
Truck Year
1977
Truck Model
c10
Engine Size
350
That's what I was wondering. A quick phone call would answer that question, but that's up to the members working on GMCs.
 

IDtag

Junior Member
Joined
Jun 20, 2024
Posts
16
Reaction score
35
Location
Oregon
First Name
Tod
Truck Year
1982
Truck Model
C30
Engine Size
6.2
I ended up buying a flip kit, said will get me about 7 to 8 but can use shackle extenders to get it back to 5 or 6. Not ideal but will see how low it actually ends up. In the middle of a house remodel and keeping the wife happy is more important than getting the truck done so the dually sits and waits.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,421
Reaction score
8,631
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
If and when you lower your truck, please post pics. I want to do that with my 84 C2500, but not so low. Maybe just a couple inches.
Your truck will be easy,front drop spindles and rear shackles,it will even ride like it does now. Steering geometry and spring rate will be same as factory.
 

Latest posts

Forum statistics

Threads
44,131
Posts
949,959
Members
36,232
Latest member
dljohnson55
Top