Author Topic: I bit the bullet this weekend V20 burb to K5 swap  (Read 12757 times)

Offline MuddiGGEr25

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I bit the bullet this weekend V20 burb to K5 swap
« on: February 26, 2017, 08:57:43 PM »
My wife and i went and picked up a 1986 K5 silverado this weekend, its a little rougher for the wear + hitting black ice in a whiteout blizzard in the middle of the night and ending up in the ditch didnt help matters, but its home now.

A few pics at the public link at the bottom, im gonna take better ones tomorrow once its sunny out so i can get clear pics

 Odo shows 23181 so im gonna assume 123K or 223K, based off the minimal rust id say probably the 123K no back seat, but i am gonna see if i can put the 3rd row from the suburban in there.

The interior seems complete, needs a good detailing and probably a few lightbulbs.

PO removed the crate 350 engine and rebuit trans/tcase and sold us the roller for $200




Next weekend my wife and I are gonna pull the TBI350, TH350, NP208 out of cliffy and transplant it into the blazer, other than possibly some fun with the wires for the TBI should be a straightforward swap.

Does anyone on here know if we will be able to pull the radiators and be able to just swing the entire combo out of the suburban and into the blazer? eg. unbolt the driveshafts, crossmembers and engine mounts, all the wires and exhaust then just move the whole shanabang( engine/trans/tcase)  and bolt it into the blazer?


We will be keeping the 10bolt axles... for now, but i am keeping the 14bolt rear and the 8lug 10 bolt off the burb before crushing it so i will have spares.

What size tires are ok for 3.42 geared 10bolt axles? 35x12.5? 37x14? I have 18.4-16.1 ag tires to put on it next year but for now just want to run what the axle can withstand under decent abuse, mostly mud, some dirt and swamps. it will rarely see roads, except when my wife wants to take it to work, the tag says 31's came with it but im quite sure the ones on it are smaller than 31's bc the 235/85r16 on the burb are much taller



Any other advice before we begin would be appreciated too.

Both diffs will be inspected and fresh syn fluid, and fresh antifreeze too.

We will also be installing the aux rear heater into the blazer, if nothing more than to provide a "mini" radiator in the back during the summer, based off the size it can remove 10-14K BTU from the engine, and i noticed 2 summers ago when i was bog racing i could drop the engine temp 5-10F by turning it on, especially when the front rad was getting clogged with mud -.- lol


https://www.facebook.com/MudiGGer25/posts/10210311243790272


In case anyone was wondering, its not gonna get a major lift or anything for now, just maybe 1" add-a-leaf for the front and 2" block for the rear, i dont want to swap springs right now because i dont want a harsh ride lol
1988 V10 Suburban 5.7L TBI/TH350 39K on rebuild 4.10AR GM14FF/GM10SF 235/85R16 & 18.4-16.1

1988 V20 Suburban 6.2L-J/TH400 CA truck, 125K G80 14FF/ GM10 4.10AR GVWR 8,600

1977 Ford Granada ~450HP 302 2bbl/C4 27K original 2.47 215/70R14

Offline MuddiGGEr25

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Re: I bit the bullet this weekend V20 burb to K5 swap
« Reply #1 on: February 27, 2017, 04:19:45 PM »
... paging 1..2...3... anyone out there lol
1988 V10 Suburban 5.7L TBI/TH350 39K on rebuild 4.10AR GM14FF/GM10SF 235/85R16 & 18.4-16.1

1988 V20 Suburban 6.2L-J/TH400 CA truck, 125K G80 14FF/ GM10 4.10AR GVWR 8,600

1977 Ford Granada ~450HP 302 2bbl/C4 27K original 2.47 215/70R14

Offline 1967KaiserM715

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Re: I bit the bullet this weekend V20 burb to K5 swap
« Reply #2 on: February 27, 2017, 05:52:31 PM »
Removing front core support will help, so you may be able to lift and place the whole engine/tranny combo as a unit.

I wouldn't go above 35" tires on a 10 bolt, and you'll likely not fit anything above 32" without some sort of lift.


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Offline MuddiGGEr25

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Re: I bit the bullet this weekend V20 burb to K5 swap
« Reply #3 on: February 27, 2017, 07:23:30 PM »
sorry im not sure what your meaning by front core support, is that under the radiator or the condensor? both of those will be removed on both vehicles, as well as alt and PS pump/fan and shroud, im thinking of just bolting the Tcase separately to make it a little easier, and i can open it, inspect it and reseal that stubborn side that leaks still. the engine and trans only have 38K on thier rebuilds so im not worried about them.


Thought of another question while i was at work today, will a 1977 small block 400 AC compressor fit onto the 1987 engine block? its TBI so its still the old style with passenger side alt and drivers side AC and PS pumps....  i did get the serp belt combo for the alternator, i could find scrap brackets if need be, but i think it would be the right compressor.


The current plan is to just run the 225/75r15 that are on it for a few months and see whats out there for 35's maybe just 33's im gonna do the cheap mans lift, just put the HD 3 leaf front springs on it and the zero rate add a leaf from ORD, and then see what size block i would need to have the back end up about 1' higher than the front when not loaded, so when we have gear in it we should still be pretty level. i think i should gain 2-2.5" in the front that way.

Just so yall know i have a 8lug GM 14FF rear that can go on this blazer and i can easily grab a set of 8x6.5 to 6x5.5 adapters online that are only 1.5" thick, so it wouldnt affect the look very much, im just not sure how sturdy the front 10bolt axle is and how hard it would be to swap to a 4.10 ring and pinion


I think with my wife helping that we should be able to pull off the swap in one afternoon and wiring the next morning ( i hope)

1988 V10 Suburban 5.7L TBI/TH350 39K on rebuild 4.10AR GM14FF/GM10SF 235/85R16 & 18.4-16.1

1988 V20 Suburban 6.2L-J/TH400 CA truck, 125K G80 14FF/ GM10 4.10AR GVWR 8,600

1977 Ford Granada ~450HP 302 2bbl/C4 27K original 2.47 215/70R14

Offline Captkaos

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Re: I bit the bullet this weekend V20 burb to K5 swap
« Reply #4 on: March 01, 2017, 12:18:10 PM »
30 or 31 will be ok with the 3.42's, anything bigger I would regear.

Chris Lucas
73-87chevytrucks.com
squarebody.biz


Offline fitz

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Re: I bit the bullet this weekend V20 burb to K5 swap
« Reply #5 on: March 01, 2017, 01:00:31 PM »
In my younger days I was grenading 10 bolt rears (3.42 gears) running 33" tires.
As far as removing the engine/trans/transfer case as 1 unit, i don't think so.  I tried it before with a 6.2 diesel, turbo 400, 208 set up and I couldn't get it done. I had the radiator support out then I tried it.

Offline 1967KaiserM715

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Re: I bit the bullet this weekend V20 burb to K5 swap
« Reply #6 on: March 01, 2017, 04:26:40 PM »
The whole front end with the lights that the radiator bolts too. I've never tried to remove the whole engine with a transfer case before, only with a tranny, and sometimes it was touch and go to get over the front.


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Current Vehicles:1985 GMC K10(Daily) 1991 GMC K2500(Daily) 1975 Beetle(not running) 1985 Mercedes 300D(not running) 1952 M35    1967 M715(not running)
 1986 Chevy K30(under repair)

Offline MuddiGGEr25

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Re: I bit the bullet this weekend V20 burb to K5 swap
« Reply #7 on: March 01, 2017, 05:26:47 PM »
30 or 31 will be ok with the 3.42's, anything bigger I would regear.

Chris Lucas
73-87chevytrucks.com
squarebody.biz

according to the options sheet in the glovebox it came with 31x10.50r15 tires originally, and Cliffy had 3.42 10 bolt axles before i swapped in the 3/4 ton ones and i was running 30x9.50r15 and i was very pleased with the amount of oomph vs weight, 0-60 times were 7-8 seconds steady, only got rid of them bc PO has run the bearing down then used a saver bearing then wore that one out too. IMO 10 bolt axles are a bit on the weak side for a 6,000+lb truck and 7,500 with passengers and gear lol, i would think with the blazer being 2500lbs lighter i might be comfortable with 33's not sure though

In my younger days I was grenading 10 bolt rears (3.42 gears) running 33" tires.

If the 10bolt rear cannot take it, can the front? ive read that the 10bolt front is on par with a dana 44 for strength and uses a regular open diff

As far as removing the engine/trans/transfer case as 1 unit, i don't think so.  I tried it before with a 6.2 diesel, turbo 400, 208 set up and I couldn't get it done. I had the radiator support out then I tried it.

Ive decided to remove the Tcase first so i can inspect/rebuild and reseal the leaky edge, then its just a matter of squeezing the 5.7L/TH350 out of there,  i would think that if i put the front on stands  so as to angle the truck up and off the leaf springs i would gain 10-12" of clearance... thats what i had to on our class C motorhome when i put in the 454..../b]

The whole front end with the lights that the radiator bolts too. I've never tried to remove the whole engine with a transfer case before, only with a tranny, and sometimes it was touch and go to get over the front.
Thanks for clearing that up


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New question, kinda.

I have the 14FF rear and corp 10 front i put on Cliffy the donor, they are geared 4.10, but the front ( 8 lug 10 bolt) looks like this:  /---{}---\ and the 10 bolt on the k5 looks like this: |---{}---|, how hard would it be to swap the 4.10 ring and pinion from the 3/4 ton into the 1/2ton 10bolt and maybe swap all the 8 lug stuff over too? I can keep it 6lug and just grab a set of 8lug to 6 lug adapters for the rear, thats totally an option if needed to simplfy the process.
1988 V10 Suburban 5.7L TBI/TH350 39K on rebuild 4.10AR GM14FF/GM10SF 235/85R16 & 18.4-16.1

1988 V20 Suburban 6.2L-J/TH400 CA truck, 125K G80 14FF/ GM10 4.10AR GVWR 8,600

1977 Ford Granada ~450HP 302 2bbl/C4 27K original 2.47 215/70R14

Offline Irish_Alley

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Re: I bit the bullet this weekend V20 burb to K5 swap
« Reply #8 on: March 01, 2017, 07:32:04 PM »
why not replace the ball joints?
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Offline MuddiGGEr25

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Re: I bit the bullet this weekend V20 burb to K5 swap
« Reply #9 on: March 02, 2017, 12:05:58 AM »
I was told the axle itself is worn, I get very little play when I jack it up and put a 6ft pry bar under it. it spent 380K under a 3/4 ton 6.2l God knows how much abuse it took
1988 V10 Suburban 5.7L TBI/TH350 39K on rebuild 4.10AR GM14FF/GM10SF 235/85R16 & 18.4-16.1

1988 V20 Suburban 6.2L-J/TH400 CA truck, 125K G80 14FF/ GM10 4.10AR GVWR 8,600

1977 Ford Granada ~450HP 302 2bbl/C4 27K original 2.47 215/70R14

Offline Irish_Alley

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Re: I bit the bullet this weekend V20 burb to K5 swap
« Reply #10 on: March 02, 2017, 01:11:48 AM »
ball joints will break before the axle gets worn. could even be wheel bearings the only thing i can think of would be a bent axle but ive never seen one and dont see how its possible
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline fitz

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Re: I bit the bullet this weekend V20 burb to K5 swap
« Reply #11 on: March 02, 2017, 04:07:26 AM »
ball joints will break before the axle gets worn. could even be wheel bearings the only thing i can think of would be a bent axle but ive never seen one and dont see how its possible
I've seen a bent axle tube before.  The same Jimmy that I was blowing up the rear 10 bolts on also suffered a bent front axle housing.
Looking back, going over jumps and getting the truck airborne wasn't  the smartest thing to do.

Offline Irish_Alley

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Re: I bit the bullet this weekend V20 burb to K5 swap
« Reply #12 on: March 02, 2017, 03:18:06 PM »
ive seen bent trailer axles from being over loaded. dont think an engine would overload the front axle. some nice air time, yes i could see that lol
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline fitz

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Re: I bit the bullet this weekend V20 burb to K5 swap
« Reply #13 on: March 02, 2017, 08:02:14 PM »
.
some nice air time, yes i could see that lol

The price for a low mileage, clean, ready to bolt in 10 bolt front axle in 1992 was $450.  The fact that it still brings back great memories today, priceless.


Offline Irish_Alley

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Re: I bit the bullet this weekend V20 burb to K5 swap
« Reply #14 on: March 02, 2017, 10:13:50 PM »
something you dont really think about growing up is the effect of gravity. i took my grandmothers aerostar on a slight jump, i dont think i got that much air but when it landed my tool box that was sitting in the back almost collapsed when i hit ground. once i came to a stop i opened the door and rolled out in pain and from laughing so hard
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes