Author Topic: 85 K5 Blazer LS swap  (Read 14816 times)

Offline acefoxx

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85 K5 Blazer LS swap
« on: October 05, 2014, 06:30:15 PM »
I'm starting an LS swap in my 85 K5. I could use any advise anyone may have. Here is what I have and know I need.

I have a 2000 Z71 5.3, complete with harness and computer
I have some motor mount adapters on order
Already running and EFI on truck so it has a fuel system
Need
700r4 spacer and flex plate kit
TV cable adapter kit
Speedo cable pulse kit for computer
Fuel line adapters

I need to find that Novak A/C kit for stock compressor and the serpentine style A/C lines

Anything I'm missing?





'84 GMC SierraClassic/'85 K5 Blazer Silverado
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Offline mizozuman2

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Re: 85 K5 Blazer LS swap
« Reply #1 on: October 06, 2014, 11:56:15 AM »
I may be wrong, but if you get 1" setback engine mount plates, it puts the engine in the same spot as a regular SBC. which means you wouldn't have to get an adapter plate for the trans?

I might be wrong, I don't know much about these LS swaps. I'm doing my blueprinting right now.
1986 Chevrolet C10 "Heavy Half"
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Offline acefoxx

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Re: 85 K5 Blazer LS swap
« Reply #2 on: October 06, 2014, 04:36:37 PM »
The 700r4 adapter is for the flex plate. The bell housing bolts up fine. It is the crank that is shorter in the back and requires a spacer/adapter.
'84 GMC SierraClassic/'85 K5 Blazer Silverado
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Offline Captkaos

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Re: 85 K5 Blazer LS swap
« Reply #3 on: October 07, 2014, 01:21:40 PM »
What EFI is on the truck now?  aftermarket?
You need a LS equivalent pump to feed the injectors.
I personally would eliminate all rubber hoses and if it is low pressure fuel hose you have to replace it.  I suggest getting teflon or E85 safe hose.
you will need someone to get into the ECM prior to cranking it.

Offline acefoxx

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Re: 85 K5 Blazer LS swap
« Reply #4 on: October 07, 2014, 03:41:56 PM »
Right now I got a tired old 350 running the PowerJection III. I had to upgrade the silly little pump they send with it cause it craps out after two months (twice). I have an EFI rated pump with steel braided AN lines. The ECM is already on it's way to the programmer.
'84 GMC SierraClassic/'85 K5 Blazer Silverado
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Offline acefoxx

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Re: 85 K5 Blazer LS swap
« Reply #5 on: October 08, 2014, 04:44:24 PM »
Can anyone confirm the year and model exhaust manifolds that will fit the LS in the 85 blazer frame? I was told 2013+ Camero, 2??? Trailblazer SS, 2??? SSR's.
'84 GMC SierraClassic/'85 K5 Blazer Silverado
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Offline Captkaos

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Re: 85 K5 Blazer LS swap
« Reply #6 on: October 09, 2014, 07:19:58 PM »
The Camaro should work and 4th gen LS f-bodys are supposed to work also.
Not familiar with the PowerJection setup, is it an external or intank setup?  If it is external that is assisting in them burning up.

Offline acefoxx

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Re: 85 K5 Blazer LS swap
« Reply #7 on: October 11, 2014, 03:43:04 PM »
The fuel pump is external, but the cheap one they put with the Powerjection III kits are worthless. I put a higher quality pump in place and it has been working great for awhile now.

Here is the PowerJectionIII kit

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Offline acefoxx

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Re: 85 K5 Blazer LS swap
« Reply #8 on: October 13, 2014, 01:38:24 PM »
Got the old one out. Waiting on some parts and me to redo the wiring harness before I set the new one in there.

'84 GMC SierraClassic/'85 K5 Blazer Silverado
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Offline Captkaos

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Re: 85 K5 Blazer LS swap
« Reply #9 on: October 14, 2014, 01:31:19 PM »
nice progress...

Offline acefoxx

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Re: 85 K5 Blazer LS swap
« Reply #10 on: November 14, 2014, 09:57:48 PM »
I have finished the LS swap into my Blazer. Here are some pics and info I collected along the way.

The wiring was not as hard as I thought it would be once I got it started.



Here are all the wires no longer needed and piled up on the ground.


I spun the injectors around so the wires could be hidden under the fuel rails


The new fuse block was a little slow for me. Had to follow the online instructions one step at a time.


Had to order and stall this crankshaft bushing in order to fill the gap between the newer motor and the older 700R4 trans in the truck.






These are the motor mounts I had to use in order to push the motor far enough back to prevent me from moving the trans forward like most ppl seem to do.




Used a freeze plug to fill in the old EGR port.


I tapped a port onto the back of the water pump to vent the steam ports from the heads.


I got lucky and the power steering line fit right into my gear box.


Here are the AN fittings that adapt to the push on style fuel rails.


This is the TV cable kit for the 700R4


Here is a shot of the SS block huggers and the old style oil pressure sensor tapped into the strange fitting near the oil filter.


I had to get another AC compressor because it was just as cheap as switching the pulley out on the old one.


I have some videos of it installed and running. I'll get them uploaded next.
'84 GMC SierraClassic/'85 K5 Blazer Silverado
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Offline FlatBlack77

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Re: 85 K5 Blazer LS swap
« Reply #11 on: November 15, 2014, 06:33:35 AM »
AWESOME job dude!
"When you are a hammer, everything looks like a nail"
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Offline acefoxx

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Re: 85 K5 Blazer LS swap
« Reply #12 on: November 15, 2014, 07:44:08 AM »
Here is a short video of it running.
'84 GMC SierraClassic/'85 K5 Blazer Silverado
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Offline frotosride

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Re: 85 K5 Blazer LS swap
« Reply #13 on: November 28, 2014, 07:04:25 PM »
Lookin good. You got it moving yet? It's good to know that the dirty dingo mounts work before I bought them. I can't wait to have more power and a better platform to build off of.. Where did you get the TV cable bracket? What about the fuel lines from the tank. I saw the AN adapters on the fuel rail and you said you already had new hoses ran but did you use the same fittings on the OE style sending unit or did you change it?
« Last Edit: November 28, 2014, 07:07:41 PM by frotosride »
"Beat it like a red-headed ford"
1987 v10 Silverado 4" RC, 35's, 700R-4, 3.73
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2009 Jeep XK, 2" lift springs in mail (future LS Swap)
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Offline acefoxx

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Re: 85 K5 Blazer LS swap
« Reply #14 on: November 28, 2014, 08:24:42 PM »
Lookin good. You got it moving yet? It's good to know that the dirty dingo mounts work before I bought them. I can't wait to have more power and a better platform to build off of.. Where did you get the TV cable bracket? What about the fuel lines from the tank. I saw the AN adapters on the fuel rail and you said you already had new hoses ran but did you use the same fittings on the OE style sending unit or did you change it?

I used an edelbrock inline 90 psi fuel pump. Mounted it right on the frame in front of the tank. Ran AN lines from it to the eng. Yes I do have it driving. I love the modern eng reliability and power. I got the TV cable from bowtieoverdrives.com
'84 GMC SierraClassic/'85 K5 Blazer Silverado
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