Frame swap question

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.

richiemoe

Full Access Member
Joined
Jul 7, 2017
Posts
63
Reaction score
13
Location
West Michigan
First Name
Rich
Truck Year
1986
Truck Model
K10
Engine Size
4.3L
I found an '82 6.2L diesel with a short box. It didn't have a lot listed, but the guy said it is a k20?!?! I didn't know k20 came in short box? Even if he is wrong, i assume it is a k10, i can use the frame to restore my '86 Custom Deluxe k10, right? Just stay away from c10? Different motor mounts? Anything else need to be altered?

At work and not a lot of time to research this. Going to try looking at it tonight if i can use it.
 

Blue Ox

Turning Diesel Fuel Into Fun
Joined
Mar 27, 2018
Posts
4,831
Reaction score
10,632
Location
LI-NY
First Name
Derek
Truck Year
MCMLXXXV
Truck Model
K20HD
Engine Size
6.2L
They didn't. It's a K10.

I don't think there's any reason it wouldn't work, but I'm not intimately familiar with all the nuances of frames. Someone else here should be able to help you out.
 

richiemoe

Full Access Member
Joined
Jul 7, 2017
Posts
63
Reaction score
13
Location
West Michigan
First Name
Rich
Truck Year
1986
Truck Model
K10
Engine Size
4.3L
Good to know, thanks! He didn't give me a price yet, but i think I'm sold on it! Haha

For the sand dunes, should i use the axles already on it? I assume they are different on a diesel than my 4.3l v6? The diesel bed has two fuel tanks, so I'll hold out for a single.
 

Blue Ox

Turning Diesel Fuel Into Fun
Joined
Mar 27, 2018
Posts
4,831
Reaction score
10,632
Location
LI-NY
First Name
Derek
Truck Year
MCMLXXXV
Truck Model
K20HD
Engine Size
6.2L
The diesel probably has a fairly low gear ratio, like 3.73 or 4.10. That may help you or not.

Why not go for the dual tanks? The shortbed only had 16 gallon tanks to start with. Just having one means a lot of stops for gas.
 

richiemoe

Full Access Member
Joined
Jul 7, 2017
Posts
63
Reaction score
13
Location
West Michigan
First Name
Rich
Truck Year
1986
Truck Model
K10
Engine Size
4.3L
After searching around for stock options, I'm thinking it is 3.73.

I'm still learning gearing, but my wife's '95 Wrangler has a small 4 cylinder, 5spd manual and 4.10 gearing. In 4x4 low, that thing hauls up steep sand dunes, with 31's. Iffy on the highway, but i can still drive in 5th, just downshift on large hills. If i stick with 3.73 with a 4.3l or put in a V8, seems like there would be enough power for 31's, right? I see a lot of forums say go with 4.56. That seems like overkill with 31's. But they are also running 33's, 35's and larger... I'm only doing a 2.5" suspension lift(someday). I want it to look smooth and clean cut...

Good idea about the gas tanks. It would give me options when looking for a short box, down the road. Once i pick up this frame, it is getting dropped off to be sand blasted, first thing! Weld in any patches if needed, then truck bed coat the whole thing!!!
 

Blue Ox

Turning Diesel Fuel Into Fun
Joined
Mar 27, 2018
Posts
4,831
Reaction score
10,632
Location
LI-NY
First Name
Derek
Truck Year
MCMLXXXV
Truck Model
K20HD
Engine Size
6.2L
The gearing question is pretty complex. You'd need the power curves of the engine and then there's a lot of math for gear ratios of the axle, transmission, tire circumference etc. There are calculators available, but you're still going to need the power curves. You can get the specifics for your model year from the gm heritage center.

Good luck with the project. It sounds like a good one, and (of course) take lots of pictures.


Oh,.. and post them here. ;)
 

richiemoe

Full Access Member
Joined
Jul 7, 2017
Posts
63
Reaction score
13
Location
West Michigan
First Name
Rich
Truck Year
1986
Truck Model
K10
Engine Size
4.3L
Ah, i didn't realize it was that involved... But i'd rather put in the time figuring out before, than to guess and be wrong...
The are fun projects, i'm use to "need this done now so it can be driven tomorrow" projects... UGH!!!
And it will be a fun project with my dad!

I will most definitely post a lot of pictures there!!
Here are a few:
https://www.gmsquarebody.com/threads/restoring-my-dads-86-custom-deluxe.19065/
 

75gmck25

Full Access Member
Joined
Oct 13, 2016
Posts
2,017
Reaction score
1,808
Location
Northern Virginia
First Name
Bruce
Truck Year
1975
Truck Model
K25 Camper Special TH350 NP203
Engine Size
5.7
A diesel short-bed K20 (or K10) sounds like an unusual combination, so I would be afraid of it being something cobbled together by a PO. I would ask him for the VIN number on the dash so you can check it.

Frames should be the same for diesel or gas engines, and any unique parts (motor mounts, etc.) can be swapped from one to the other. AFAIK, the only frames with significant differences are the one ton frames. Cabs are different for 2WD/4WD because of the larger hump needed to clear the transfer case.

I have 4.10 gears and stock height 31" tires, and its not a problem on the highway. 3.73 might be a little more flexible, but I don't have problems with 4.10 gearing.

Bruce
 

richiemoe

Full Access Member
Joined
Jul 7, 2017
Posts
63
Reaction score
13
Location
West Michigan
First Name
Rich
Truck Year
1986
Truck Model
K10
Engine Size
4.3L
I wondered about that as well, but it is definitely a k10. The owner thought it was a k20, which being a diesel, i would have assumed as well. But looking at the specs, there was no k20 diesel.... The owner had bought it to restore his '79 short box.

Thanks, i wasn't sure about the motor mounts, or how simple they were to swap. It is definitely a 4x4, so i feel better about that. Plus i'll be using my '86 k10 cab.

For what i'll use it for, i think 4.10 will be great. Since i'll have an extra set of axles, it might be a good opportunity to teach myself how to re-gear. If the '86 is 3.73 or 4.10, i'll keep it how it is. I'm quite sure the diesel is in the high 2', low 3's...
 

Dooley

Full Access Member
Joined
Mar 19, 2014
Posts
364
Reaction score
947
Location
North Coast
First Name
RW
Truck Year
1988
Truck Model
V30
Engine Size
454
The military M1009 Blazers of the middle 80's came factory equipped with the 6.2 followed by a T400 and 3.08 gears.
Stock tires were 31/10.50-15's.
Milne was upgraded in civilian life to a 700R4 and works great!
My M1008 5/4 ton had 4.56's and the 6.2 was screaming at 60 mph with 255/85-16's.

You must be registered for see images attach


You must be registered for see images attach
 
Last edited:

malibuman402

Member
Joined
Aug 2, 2015
Posts
44
Reaction score
40
Location
nc
First Name
Larry
Truck Year
1984
Truck Model
C10 Silverado
Engine Size
BB 402+.060 = 413.8CI
2 wheel drives came with the hump if it came with a standard trans.
 

Latest posts

Forum statistics

Threads
41,850
Posts
903,458
Members
33,362
Latest member
Dhatch84
Top