can you D30 to K20 front leaf swap??

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.

TigerTodd

Junior Member
Joined
Jan 17, 2020
Posts
25
Reaction score
30
Location
san diego
First Name
todd
Truck Year
1982
Truck Model
k20
Engine Size
6.2
so i have a 1982 K20 4x4 6.2L and i just put 285/75/16 MT tires on there. They are pretty stuffed and rarely/barely rub with the stepsides taken off. I need a 2 inch lift... so I also have 1986 D30 M1008 that im going to put a 4" lift on with 37's....

So my question is.. can i swap the D30 front leafs to the K20?

I looks like they are the same length at 47'' and about 24'' to the center of the axle measured from the front of the leaf to the axle. the bolt up is different but i dont think it will matter as i'll need new u-bolts anyways because the d30 is 3 leafs vs. 2 on the k20.

I was thinking of a flip shackle for the rear or 2'' blocks.. or whatever is level after the swap.

thanks in advance!

You must be registered for see images attach


You must be registered for see images attach


You must be registered for see images attach
 

nvrenuf

Full Access Member
Joined
Jul 30, 2010
Posts
1,981
Reaction score
2,522
Location
Mobile, Al.
First Name
John
Truck Year
1991
Truck Model
K5
Engine Size
454
Yes, the front springs are interchangeable between all of the 73-87(91) square body trucks. The only difference in the springs is what you've already seen - 2 vs 3 springs - which is determined by the front suspension option(s) ordered.
 

TigerTodd

Junior Member
Joined
Jan 17, 2020
Posts
25
Reaction score
30
Location
san diego
First Name
todd
Truck Year
1982
Truck Model
k20
Engine Size
6.2
Yes, the front springs are interchangeable between all of the 73-87(91) square body trucks. The only difference in the springs is what you've already seen - 2 vs 3 springs - which is determined by the front suspension option(s) ordered.

right on.. thank you. hopefully the D30's will give me the 2'' i need.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,637
Reaction score
28,911
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
right on.. thank you. hopefully the D30's will give me the 2'' i need.

Not likely. Height will be about the same unless the original springs are very worn, but the pictures show springs with similar arch.
 

nvrenuf

Full Access Member
Joined
Jul 30, 2010
Posts
1,981
Reaction score
2,522
Location
Mobile, Al.
First Name
John
Truck Year
1991
Truck Model
K5
Engine Size
454
Agreed. Most likely, the only height you’ll gain is the thickness of the 3rd spring (3/4”?).
 

Craig 85

Full Access Member
Joined
Jan 25, 2017
Posts
3,918
Reaction score
4,129
Location
Nashville, TN
First Name
Craig
Truck Year
1985
Truck Model
K30 SRW
Engine Size
454/TH-400/NP205
If you buy the grease able shackles front from ORD they are 1/2" longer. It will net you another 1/4"
 

Dooley

Full Access Member
Joined
Mar 19, 2014
Posts
377
Reaction score
988
Location
North Coast
First Name
RW
Truck Year
1988
Truck Model
V30
Engine Size
454
I am curious why you are having clearance issues.
I have run 235/85-16's for years without any problems and 33/12.50-15's on the half ton with an 8.5 Western Pro Plow also.
What is the wheel width and spacing of the hub?
Likely the rub is with the running board on the passenger side, correct?
K, V, or D springs alone won't give you lift.

You must be registered for see images attach
You must be registered for see images attach
 

Blue Ox

Turning Diesel Fuel Into Fun
Joined
Mar 27, 2018
Posts
5,256
Reaction score
12,184
Location
LI-NY
First Name
Derek
Truck Year
MCMLXXXV
Truck Model
K20HD
Engine Size
6.2L
Likely the rub is with the running board on the passenger side, correct?

Now, this is an interesting observation. That's exactly the problem I'm having with slightly larger tires on my truck. They fit fine on the Suburban with running boards, but I had to take the right side running board off the pickup. I just @$$umed the cab was crooked from a previous accident. Is there some asymmetry in the pickups that I'm not aware of?
 

Dooley

Full Access Member
Joined
Mar 19, 2014
Posts
377
Reaction score
988
Location
North Coast
First Name
RW
Truck Year
1988
Truck Model
V30
Engine Size
454
Now, this is an interesting observation. That's exactly the problem I'm having with slightly larger tires on my truck. They fit fine on the Suburban with running boards, but I had to take the right side running board off the pickup. I just @$$umed the cab was crooked from a previous accident. Is there some asymmetry in the pickups that I'm not aware of?

I have always believed there was a slight steering symmetry to this observation.
Around here going back to the mid 70's it was usually told as,"they all do that".
I had new GM's as well as used ones encounter the same affliction with boards attached. Seen guys loosen cab mounts and try to"square up" the cab using their phrasing with no change in result. I beat the running board back with a BFH on one old truck once for a modicum of extra clearance on an old Suburban running 33's on 10" wide Jackman rims.
 
Last edited:

QBuff02

I like Big Blocks and I cannot lie
Joined
Feb 28, 2017
Posts
867
Reaction score
1,598
Location
Central IL
First Name
Quincy
Truck Year
1982
Truck Model
K30
Engine Size
454
Now, this is an interesting observation. That's exactly the problem I'm having with slightly larger tires on my truck. They fit fine on the Suburban with running boards, but I had to take the right side running board off the pickup. I just @$$umed the cab was crooked from a previous accident. Is there some asymmetry in the pickups that I'm not aware of?

I've often wondered that myself! On my '82 K30 there is a noticeable difference in how the tire/wheel sits in the fender opening between driver and passenger side. The passenger side sits probably a good 3/4" farther back in the opening than the driver side but the truck drives straight down the road. But yet by all measurements on the frame and driveline everything is square.
:shrug:
 

Blue Ox

Turning Diesel Fuel Into Fun
Joined
Mar 27, 2018
Posts
5,256
Reaction score
12,184
Location
LI-NY
First Name
Derek
Truck Year
MCMLXXXV
Truck Model
K20HD
Engine Size
6.2L
Interesting. I know mine was hit hard in it's youth, but it measures square on the diagonals from the ball joints to the rear spring bolts. And same thing, it drives straight AFAIK.

At some point I'm going to do a frame off and will measure the cr@p out of it. Even if it's just to assure myself that they actually got the frame straight after the accident. I'll report when and if that ever happens.
 

TigerTodd

Junior Member
Joined
Jan 17, 2020
Posts
25
Reaction score
30
Location
san diego
First Name
todd
Truck Year
1982
Truck Model
k20
Engine Size
6.2
I have run 235/85-16's for years without any problems and 33/12.50-15's on the half ton with an 8.5 Western Pro Plow also.
What is the wheel width and spacing of the hub?
Likely the rub is with the running board on the passenger side, correct?
K, V, or D springs alone won't give you lift.

You must be registered for see images attach
You must be registered for see images attach
[/QUOTE]


I took off the running boards.. its just as tight of a fit as you can get on my truck, slight rubs over speed bumps ands what not.. if you went wheeling you definitely would rub more i think.
 

Forum statistics

Threads
44,423
Posts
957,433
Members
36,769
Latest member
Bowtie72
Top