72 blazer ls swap
 

So I'm fare lyrics new to the site and purchased my blazer about 6 months ago. I love driving it so much I did a lot of research on this site and decided I would try my first ls swap. I will start by saying thank you to everyone for all the info. I'm hoping that this build might help someone else. After gathering some parts I started my project right after Christmas.

Since I did not want to stop driving the truck and wanted a lift kit I decided to start with a second frame. After having it sand blasted we added some bracing to help stiffin the body for towing. I decided to use a 31 gallon tank from a 87 blazer to be able to have an in tank fuel pump. To mount it I took 2 pieces of 2x2 angle and welded them together. This aligned to the rear set of rivet holes for the bump stop mounts. The original gas tank brace will need to also be moved back to fit the tank. This aligned with a set of holes already in the top of the frame to give you a reference point.

Re: 72 blazer ls swap
 

Here is some on the reinforcement I did to the frame. The biggest improvement came from boxing in the original crossmember. For that I used a piece of 2x3 square stock and cut it to fit.

Re: 72 blazer ls swap
 

Once the gas tank was fitted it was time for paint and reassembly. I por 15 everything then top coated with Eastwood chassis black but had issues with drying, it took over a week to cure. Not sure that was a good combo to use. After that the 4" rough country lift was installed with 3/4 ton axles from a 86 suburban

Re: 72 blazer ls swap
 

I landed a 2002 suburban with 140k miles. 5.3l and 4l60e. Since my blazer has a np203 I decided to go back to a np205 and bought the AA adapter kit. I was going to fabricate a new cross member but due to time I ordered a dirty dingo crossmember. Once that comes in I can start on the brake lines.

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As for the fuel system I decided on trying the poly fuel lines after reading hemi43's thread. I bought a factory sending unit for the 87 blazer and cut off the flare fittings. Dorman sells a repair kit that has 2 12" lines with the quick connect ends. You can cut them to length then use a flaring block and swage to expand the pipe. Then brazed them together with 45% silver braze. Then added an Acdelco ep381 fuel pump that plugs right into the sending unit. I still need to find a fuel filter that has the quick connects. I think the early 2000s mustangs will work.

Re: 72 blazer ls swap
 

Looking good so far! You did your homework!

Re: 72 blazer ls swap
 

Subscribed.

Re: 72 blazer ls swap
 

Thanks Keegan. The idea of a second frame and the tank setup came from you. I've probably read your build about 15 times now.

Re: 72 blazer ls swap
 

Nice build....I'm subscribed....
Spare frame for me too....
I just got it in the shop and mounted to the rotisserie yesterday
Attachment 1626574

Re: 72 blazer ls swap
 

Looking good!! You won't regret using the ploy lines, just keep them away from chaffing and the exhaust. I used a standard fuel filter like the one on your 02 donor, because it used the same connectors as the ones on the fuel sender and fuel rail. BTW, we like lots of pictures !:lol:

Re: 72 blazer ls swap
 

Good stuff,

Post good pics of the fuel system. I am doing the same.

Smitty

Re: 72 blazer ls swap
 

Keegan, you didn't have to move your cross member to mount that 31 gallon tank, did you?

Re: 72 blazer ls swap
 

subscribed

Re: 72 blazer ls swap
 

Yes, I moved it back a few extra inches but forget why. It may have been because the filler neck would have been right in the way of the body mount.

Re: 72 blazer ls swap
 

Yes the cross member needed to be moved back or the gas tank would be over the axle.

Re: 72 blazer ls swap
 

Alright so I got the dirty dingo crossmember and proceeded to paint and assemble it. There are quite a few bolts. Also I'm showing the holes that had to be drilled in the frame to mount it. Notice that you use one existing hole to mount it and one of the other holes gets very close to an existing one. Theyou do provide plates that go on the outside of the frame which I haven't installed yet.

Re: 72 blazer ls swap
 

Here is the motor installed. I used anchor 2292 motor mounts off rockauto for the frame. As for the motor side I ordered a set of IFS mounts to save some money from the dirty dingo mounts. I had to trim the tabs off the passenger side anchor mounts to allow for easier install. Since I'm running a truck pan it was very close to the crossmember as others have stated it would be. It the wording on the pan was grinder down it would allow for more clearance. I added 2 3/8" washers between the motor and IFS motors which comes out to around 1/8". I thought about making a steel plate for a spacer but the washer aren't loosing any surface area for mounting.

Re: 72 blazer ls swap
 

More pics

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So the only issue I have now is the secondary transfer case mount, which I know was not standard on all blazers does not line up. The crossmember came with the frame so I know it's correct. The transfer case was a Craigslist find and came with the secondary bracket. I believe the transfer case is stamped 72 though and the rubber mounts are new. It's looks to be about an inch off. I'm not sure if I should shim up the transfer case or just not use the other mount. Any ideas?

Re: 72 blazer ls swap
 

I see the rubber mounts on the front tire take a picture installed on the inside of the frame rail maybe something there is switched around. I know someone will know how it should look if not I can find the picture in the body and chassis manual if it comes to that.

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My bracket looks like it comes down further than that (I think). Do you have the rubber mounts in between the bottom of the t-case and crossmember installed?

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Here is what mine looks like. Maybe suck the bracket mounts down? I don't see any vertical bolts on yours.

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Dwyane, I am just holding the bracket in that picture. Friday i will mount it in with the rubber. I looked at a few pictures of this site to see how it mounted

Keegan I do have new mounts between the crossmember and the AA adapter mount. I did not take a picture of that but there there.

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Mount the bracket with the rubber and see where you compare to the pics I just posted. I have another bracket that is 72 correct if we still think that one is too shallow...

Re: 72 blazer ls swap
 

Your not hijacking, as all the questions you want. I also could not find that info. I started my own mounts then gave up. So it was easier for me to reference the head. With a straight edge laying on the frame and touching the rear mounting bolt webbing on the block, the head is slightly over an inch. I'd say 1 1/8"

I also took a picture of the gas tank to axle spacing so show why the original gas tank brace gets moved back.

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I also tried the transfer case side mount but it is was off. Keegan yours looks like it is taller. I have pictures of what mine measures if anyone has one that they can verify if this is the wrong mount.

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Thanks...much appreciated...!
I think I have a TC mount from a '71 if I can find it....I will measure it. I'm using a NP241 TC so I won't need it.

Re: 72 blazer ls swap
 

Are you planning on cutting the filler neck?

Smitty

Re: 72 blazer ls swap
 

To be honest I haven't thought that far. I was hoping the factory hose would connect to the tank. Maybe Keegan can tell someone how he did it.

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If you mounted the tank just to the bottom of the frame, I think you are going to have issues with the neck hitting the body floor unless you put spacers in on the body mounts. I put in a 2 1/4 drop on mine so the neck clears the body. Once I finish mocking it up I will post on my build. Some people cut their filler necks on the tank to make up for it. Old tank and new one has a different neck size also.

Smitty

Re: 72 blazer ls swap
 

Yea I would say yours is short

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Correct - I sandwiched my tank in so it would go any further "up" or that would have been the case. I also ended up putting some brackets between the two crossmembers to aid this even more. They run the same way as the frame. For the filler hose, I just double hose clamped the hell out of both ends. Someone showed me a link to some flared hoses at one time but I don't have it anymore.

Re: 72 blazer ls swap
 

OK I know it's been awhile since I've posted. I now have the brakes plumbed in, axles painted, brakes rebuilt and the fuel system roughed in.

Fuel system:
87 blazer tank and sending unit
Acdelco ep381 fuel pump with sock (can be ordered from a 95 s10)
Dorman 3/8" poly lines and connectors
Dorman 5/16" poly lines and connectors
Tanks fuel filter FF-10 (summit TNK-FF-10)
Dorman 3/8 and 5/16 steel line

Like most people have done I used the 87 blazer gas tank with the baffles. I showed in an earlier post how I modified the 87 sending unit by cutting off the flare nut, swagging the adapter lines and brazing them together with 45% silver braze. After some paint I installed the Acdelco fuel pump which fits right in the basket. After much searching at the local auto parts store I found summit was the only place I could find a 3/8" in and out fuel filter and it comes with a mounting bracket. Also since this is the first time I've used the poly fuel lines, I wrapped the lines with braided wire loom to help prevent it from rubbing through. As for installing the ends on the poly lines I did not want to purchase the install tool to do 6 fitting so I used the caulk gun method. Do some experimenting with it as I found it necessary to move the flare block a few times to make one fitting.

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Since the frame is almost as far as it can go it was time to disassemble the truck. Once my buddy's lift frees up I will be pulling the body off.

P.s when I bought this true it was advertised as fully restored. I guess restored is a loose term

Re: 72 blazer ls swap
 

How do like those poly lines? I'll definitely use them again.

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I like them, they are very quick and easy to install! Plus the fact that they will never rust out. I was a little worried about them rubbing through but hopefully the wire loom will eliminate that issue. Thanks for the suggestion

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For what it's worth. For extra safety, I also tie wrapped the quick disconnects on the feed and return lines at the engine's fuel rail. I din't want to rely solely on the plastic clip to hold the line on, because it if should ever pop off with the engine running it could cause a fire. Just peace of mind IMO.

Re: 72 blazer ls swap
 

I ran the poly line in my LS Wagoneer swap. You are correct to secure the ends, They will not take any dangling load off the fuel rail. In a rush to get it on the road I did not secure the fuel line to the fire wall maybe 18-24 inches and it popped off maybe 18-24 inches. luckily no fire. I went AN fittings from the fuel rail to the filter Then ploy to the tank. As fair as the filter goes The C5 vett filters have a built in regulator witch makes life easier running one one line to the motor.

Re: 72 blazer ls swap
 

Last Wednesday I drove the blazer over to my buddies house and took the the body off the fame. After a week of scraping all the undercoating and grease off the bottom of the truck and to my surprise no rust in the floor boards, just the rocker boxes. I painted the bottom with por 15 for protection.. After stripping the firewall I learned how to paint with single stage paint. I think it turned out pretty nice. Put the body on the new frame today but stI'll needs to be bolted down. As Smitty and Keegan said I did have to space the gas tank down. I found a piece of 1" square stock aluminum and installed it as a spacer. I tried to picture it before I set the body fully down. Sits a little high but I think it will look good with the top off. I may need new taller garage doors now.

Re: 72 blazer ls swap
 

Well I figure it's about time I update this build. After having a busy spring the blazer did not get done by my estimated time of memorial day but I did have it running by the 4th of July.

So because of time I opted for a wiring harness from bp automotive. This harness is layed out very nice with all wires labeled. The only thing I would suggest is calling to place the order instead of doing it online. I ended up with the wrong injector connectors due to not knowing it was a flex fuel motor. I ran the harness through the firewall behind the passenger side fuel rail and made a bracket (shown) that allowed me to mount the computer and fuse panel right under the glove box.

As for the throttle cable, I used the one off the suburban and it fits great. You will barely have to ream the hole in the firewall and then just make a slot in the gas peddle for the cable to slide into it. I also used the lokar shifter linkage which took a lot less time to install than expected.

I reused the stock radiator that was in the blazer and uses the radiator hoses off the suburban. I trimmed a few inches off the lower one. Also I drilled and tapped the water pump to connect the steam ports to.. As for fans I bought a 2004 grand cherokee fan and put it into the stock shroud. Note that the 2000 to 2003 are single speed and the 2004 is a 2 speed motor. I have yet to have it bring on high speed.

The cold air intake was a part I found at a swap meet. I believe there's a part number on it if anyone's wants me to lookeep but I know it was for a carb setup. Then just a filter and boots from summit.