Re: Doing LS Swap - I have no idea what I'm doing!
 

Pics man PICS! I am dying here!

Re: Doing LS Swap - I have no idea what I'm doing!
 

:lol: Unfortunately, I don't have anything to show. Everything is still in the box. At some point, in the future, I will have some updates and pictures to share. ;)

Re: Doing LS Swap - I have no idea what I'm doing!
 

OK, I'm sure this has probably been discussed before, or even achieved. But, I had a thought... Would it be possible to keep the stock gas tank and use it as a filler for the new tank under the bed? Are you with me?

I'm thinking, instead of adding a fill spot to the bed somewhere - keep the tank behind the seat. Run a line to the new tank as a filler hose, either gravity fed, or with an external pump (which I already have). This way, I could fill up the stock tank as always and let that fill the new tank under the bed and supply the fuel pump, basically as an auxiliary fuel cell. I get the benefit of having the baffled tank with the new equipment to supply the motor, but also a longer range due to the extra tank. Also, I won't have to fab up a fill location in the bed for the new tank. Does any of that make sense? The hose size from 1 tank to the next would probably have to be larger than what is already there, now that I think on it more. I was hoping to just use the current size coming out of the stock tank. Convert it to a hard line to keep it from sagging, or re-purpose the stock hardline to run to the back. Or, just use steel braided line and keep it from sagging too much - keep the low spots out of it.

I don't know... sometimes I overthink things, or get accused of dumb ideas - maybe this is one of them. :D What do you guys think? I'm sure if it worked, it would be talked about a lot more on here.

Re: Doing LS Swap - I have no idea what I'm doing!
 

Got some fuel line fittings ordered for the new setup. The fittings for the regulator showed up today. The adapters for the sending unit should arrive Saturday. One step closer...

Re: Doing LS Swap - I have no idea what I'm doing!
 

Took my original radiator to a shop yesterday to see if he can get it fixed up. I know it had a leak, and looks like some prior "fixes" done to it. The guy said he'd clean it up and test it, and let me know how bad it is. I'm wondering if it'll be worth the fix, or just end up with a new one.

Saw this setup the other day - starting to wonder if it may be something to try for the price. https://www.alloyworksplus.com/produ...mmy-67-72_56f0

Re: Doing LS Swap - I have no idea what I'm doing!
 

I gave up on radiator cleaning and will only do new from now on. Shops are not allowed to use the harsh chemicals used back in the day when rebuilding radiators was common. Plus the skillset is probably gone as the demand is gone.

Re: Doing LS Swap - I have no idea what I'm doing!
 

Make sure you get one for an auto trans, pretty sure that one is for manual so it won't have the trans cooler, unless you are going external cooler. That seems awfully cheap for fans and radiator...

Re: Doing LS Swap - I have no idea what I'm doing!
 

Ok... so slight dilemma. I dropped off my cpu yesterday to the shop that is going to build me a new harness and flash the cpu and tune it. He called me late last night and said, "we might have an issue... your cpu is reading as a 2005 4.8L motor". But, the VIN I got from the salvage is from a 2003 5.3L. I've gone through the different scenarios, different cpu from a donor - but it was all hooked up when I got it delivered. Now, could they have hooked it all up to deliver it? Sure. But, everything looked like it hadn't been touched.

Now, I have a pic of the underside from when I swapped the pan out, and the crank has a cast number of "12552216". When I search that number, it appears as used on the 5.3, 6.0, 6.2L engines. Would that be a tell all sign, or do I still need to look at the piston heads to tell for sure? I'm going to see if I can rent a borescope from one of the parts stores to look for sure - hopefully, I can. Any other tell-tale signs that I can look for?

Maybe they sent me the wrong VIN # - I'm sure it can happen. But, how do I really tell what I have? Do I need a legit VIN to program the computer?

Re: Doing LS Swap - I have no idea what I'm doing!
 

You have a 5.3, see here. https://sites.google.com/site/sloppy...a-4-8-or-a-5-3

Your tuner should be able to flash in anything he want's. The 4.8 and 5.3 use the same ECM, just the tune is different. I would verify your injector part # and give him that info and just let him flash in a 5.3 tune with a little more timing and turn off security and the rear 02's and go for it.

Re: Doing LS Swap - I have no idea what I'm doing!
 

The return less rail also suggests its a 05 motor
03 truck motors are a return style fuel rail

The only for sure way i know to id 4.8 vs 5.3 is pull the pan and look at the rods and crank

Real good chance your motor is an 05 4.8 ls motor
They are still a decent motor I had one in my service van ran great
The pcm should also have a vin in it for what 05 vehicle it came from

Powerblock had this happen they bought a 5.3 from the yard pushed it hard on the dyno 1000 ish hp then opened it up and discovered they got a 4.8 instead

Re: Doing LS Swap - I have no idea what I'm doing!
 

Looking at my crank, it has the part number for the 5.3. I am going to pull a plug this evening and use my new inspection camera to look at the cylinder heads. The camera arrived this morning, so hopefully I'll know something tonight.

I guess, once I determine what I have and assuming it's a 5.3, then I need to check my injectors to see if they are flex fuel type, or the other. The VIN I have from the salvage is definitely a 2003 Tahoe, 5.3L Flex Fuel (L59), 2WD.

I'll report back as soon as I look at the cylinders.

Re: Doing LS Swap - I have no idea what I'm doing!
 

Most if not all of the flex fuel engines had stainless steel fuel rails.

That doesn’t mean someone couldn’t of changed it.

Re: Doing LS Swap - I have no idea what I'm doing!
 

Alright, cylinders are dished, so that, along with the crank, verifies the motor size - 5.3 motor. Ran the TAC module number and it comes up as a '03-'05 part number. Programmer was a little concerned due to some discrepancies of PCM and TAC modules not working together.

Anyway, got that stuff worked out and he's ordered the harness and will get the PCM flashed and ready to go. It's now a waiting game for the harness to come in! Due to supply issues, it could be a couple of days - or, it could be weeks... who knows.

Re: Doing LS Swap - I have no idea what I'm doing!
 

Got the call this weekend! My harness arrived at the tuner and he was finishing up my tune. Going to pick it up sometime this week. Hopefully, I can start working on the fuel system install. Want to get the tank mounted and start running the fuel lines. To do that, I'm going to have to cut out a couple of cross-braces - one Z-style crossmember on the frame, and one of the bed braces. I grabbed a piece of 1-1/2" angle from work to use as a mount/support for the tank. I'll fit it onto the frame rails and drill it to bolt into the frame, then I can drill the mounting holes for the tank.

Question - you guys that have done the Wrangler tank, did you use any tank straps to help support the tank? Or, has it been ok to just use the tank flanges to support the tank?

Re: Doing LS Swap - I have no idea what I'm doing!
 

I need to cut this brace out to install my gas tank. Any ideas? I started the cut on either side, next to the frame. I'm thinking I'm just going to run along the top - as close as possible. Then, see if I can bend that out of the way and cut the other side of it, and hope that I have enough room.

Re: Doing LS Swap - I have no idea what I'm doing!
 

I am not a fan of using flanges on the tank to mount it. I have never seen one mounted that way from the factory. Seems like an easier less costly route. Must be a reason cars do not come that way. My thought is it may be okay for a rigid boxed or tube frame. But for an old frame that flexes and moves a bunch, not a good idea to me. A lot of people do it. Most if not all aftermarket tanks are made with flanges, which is one of the reasons I avoided aftermarket. Just my opinion.
Getting the rivets out can be a pain, but not really any harder than cutting the crossmember.

Re: Doing LS Swap - I have no idea what I'm doing!
 

I've been debating making some tank straps, or buying some, to help hold the tank in place. The tank I bought, actually has mounting holes on each corner of the tank flange, so I'm guessing that's what they are for. Now, it is only a 15 gallon tank - which I know will still be heavy when full, but, shouldn't be too bad.

Re: Doing LS Swap - I have no idea what I'm doing!
 

You haven't looked back far enough. Fords, and I'm sure most other manufacturers from about 1932 til around 1948 all had flange mounted tanks. They were notably smaller though so that may be a factor to consider.

Personally I would put straps on a tank in a truck just for the fact that if you put the flange on top of the frame, you wouldn't be able to drop the tank if need be.

Re: Doing LS Swap - I have no idea what I'm doing!
 

You are correct that I had not looked back that far. Vehicles were still in their infancy back then so I still stand by what I said.

Re: Doing LS Swap - I have no idea what I'm doing!
 

Had a little time to cut on the truck a little more last night. I was able to cut some of the bed crossmember out. I still need to get some more of it, but trying to get my Harbor Freight grinder w/ cutoff wheel up under the bed is a tight fit. I may try my Sawzall next to see if it works. I didn't get pictures - will try and get some next time I'm under there.

Re: Doing LS Swap - I have no idea what I'm doing!
 

So, it's been quite a while since I've been around, or done anything to the truck. Most of the family came down with Covid, and we lost a family member recently. But, we've been talking about getting after it again - 3-4 months later. Since most of my free time is late at night, I thought I might start trying to lay out the wiring for the motor. I don't where to start. Do I start by mounting the computer somewhere, or do I start hooking stuff up and then mount the computer to where-ever it will reach?

I ended up having a harness made and it's labeled for each connection. It's actually a PSI harness, so I'm not sure how much extra wire is there for the cpu mounting location. I haven't really looked at it too much to try and lay it out.

Re: Doing LS Swap - I have no idea what I'm doing!
 

Sorry for your loss. These are difficult times. Maybe working on the truck will help keep your mind busy. Good to see you back at it.

Re: Doing LS Swap - I have no idea what I'm doing!
 

sorry about the family situation...life happens
as far as the harness is concerned...I would make all the connections, clean up and loom the wires as best you can, then see how much slack you have left going to the PCM and relays
that will determine where to place them...the relay and fuse block should be somewhere accessible for servicing if the need arises....
if you are going to have AC....that limits the amount of room there is behind the dash.
I'm still debating where to put mine on my '67 build , I'm also adding a cruise module...so there's another component to mount....somewhere?

good luck with it...:metal:

Re: Doing LS Swap - I have no idea what I'm doing!
 

On my 68 LS swap I mounted the ECM behind the glove box along with the relays. The fuse block which has CEL light I just screwed it to heater box just low enough so I could see it from the drivers seat. I had to section the paper board glove box liner to make room for the ECM. Still had a pretty decent glove box.

Re: Doing LS Swap - I have no idea what I'm doing!
 

I took a look at my harness last night. It does have a grommet on the main harness to allow for entry through the firewall. Maybe there is enough wire there to mount inside the cab? I'm lost at electrical stuff. Luckily, the guy I dealt with labeled every connection and wire on the harness. The harness was made by PSI Conversion. Everything is already covered in wire loom and ready to go. I just have to figure out where to start as far as hooking things up and running the wires.

Re: Doing LS Swap - I have no idea what I'm doing!
 

Find the area of the harness with the coil and injector connectors. Make sure you have them on the correct sides and then just kind of lay the harness there. then move wires around seeing where they go and just have it kind of where it's going, then make adjustments accordingly.

Re: Doing LS Swap - I have no idea what I'm doing!
 

I did the wrangler tank adn built a frame around the flange, then set it on rubber. It's set up so the front rides on top and the back bolts up, so when you pull it, you can jam the front in and swing the back up. Useless pic here- http://67-72chevytrucks.com/vboard/s...=501131&page=6

and here http://67-72chevytrucks.com/vboard/s...=624310&page=7

Ah, here's a better one- http://67-72chevytrucks.com/vboard/s...=624310&page=9

Hope it helps!

Re: Doing LS Swap - I have no idea what I'm doing!
 

I like that idea! I'll probably steal that for my install. My other option was to just bolt the angle I have onto the frame and bolt the tank to that angle. That way if it ever does have to come out, I can just undo the piece of angle and take it out that way.

Re: Doing LS Swap - I have no idea what I'm doing!
 

My vote is to put the PCM under the hood if your harness will allow it. GM did it that way, it can handle the heat. The under dash is so tight that it’s hard to find extra room without compromising something else.

Re: Doing LS Swap - I have no idea what I'm doing!
 

For anybody interested this guy JR has a youtube channel where he walks you through how to do a LS swap into a squarebody. From pulling the donor engine at a junkyard and how to rig up the fuel system...

He has all kinds of info.

Here's a link to one of his playlists for a LS swap.

https://www.youtube.com/watch?v=dhVZ...WvfqpMN8YkO9ZY

Scotty Baccus has a great guide on what to do and look out for when doing a LS swap his article is at:

https://tejassteelworks.com/wp-conte...uide-73_87.pdf

I loverJR’s content…..”Buy once cry once” LOL
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Re: Doing LS Swap - I have no idea what I'm doing!
 

Well, haven't had much to post about lately - or, at all for that matter. I haven't had time to get to the truck with family time. I did spend about an hour in the garage the other night (Friday night) after everyone was asleep.

I put the exhaust manifolds on, the new dipstick tube (Super hard, I know), and started laying out the wire harness. I hooked up all the connections I could easily get to on top of the motor (injectors, alternator, coolant sensor).

I still need to verify some of the locations for the other stuff and try and get to the rear and under the motor to hook up the rest of the connections. Anybody know of a diagram that shows where all the connections are located?

Re: Doing LS Swap - I have no idea what I'm doing!
 

I don't know if I missed it, but what tank setup are you using?

Re: Doing LS Swap - I have no idea what I'm doing!
 

Here is a picture of where my ECM ended up. Yes it's connected, the wiring comes up between the fender well and the cab. I plan on painting it black but haven't got around to it yet. Factory holder behind it with a wire bail keeping it in.
My harness was a conversion, not custom, so I had only so much wire to work with.

Re: Doing LS Swap - I have no idea what I'm doing!
 

Progress is progress!! I've been trying to get my Camaro fired up so I can get the truck moved in before my first kid is here in June, never enough time! As far as "where all the connections are located?" what all are you looking for, engine sensors, truck connections, others??

Re: Doing LS Swap - I have no idea what I'm doing!
 

here's a link and a picture to the sensors on top. I'd look over at lt1swap.com and start taping off the ones getting eliminated to make it less confusing.



https://www.ls1.com/forums/f6/list-s...hey-do-159572/

Re: Doing LS Swap - I have no idea what I'm doing!
 

I'm going with the Jeep Wrangler tank. If I remember right, I ordered one for a '90 model FI tank. I'm mounting it under the bed, behind the axle.

Yea, I'm pretty sure I'm going to mount it in the engine bay. Probably on the driver side fender. I have an a/c truck, so that spot on my firewall is taken up by the heater/ a/c stuff.

If you can, get that stuff done before you have your kid! Congrats by they way! :D I've got 3 of them (oldest will be 6 in a couple of months). All of my work on the truck is after 10pm. Hence, why I haven't finished my gas tank yet - I need to cut some more metal out, but their bedrooms share the garage wall.

Anyway, I was looking for a picture of the engine that showed where each connection point was located. I think I have most of them figured out, but I second guess myself too much and worry about hooking things up correctly. I have the injectors, alternator, coolant connection hooked up. Pretty sure I can do the transmission connections. But, there are several like the oil pressure (I think it's behind the engine), knock sensors, MAF (I'm afraid I may have a wrong connection type for it), and some others that I don't remember what they are called.

Luckily, all of my connections on the wiring harness are labeled. I just need to figure out where those connections are on the truck motor. I've seen a lot videos on the car motors, but the truck intake throws me off when when looking at pictures/videos 'cause they are slightly different.

Re: Doing LS Swap - I have no idea what I'm doing!
 

Thanks! I'll check it out. It's been so long since I've done any research that I dang near forgot about lt1swap.:lol:

Re: Doing LS Swap - I have no idea what I'm doing!
 

You can buy a npt adapter for the oil pressure sender so you can mount the oil pressure sender. Not knowing your gauge set up I would run the oil pressure sender directly to your gauge not thru the ECM.

Re: Doing LS Swap - I have no idea what I'm doing!
 

I was using one of the 3 gauge pods for temp and oil pressure, previously. I don't think my dash gauges work. I still have all of the that stuff ran into the engine bay. Wasn't sure if I'd need it with the new setup or not, so I left it all accessible. If possible, I may just reconnect that stuff until I can figure out the OEM gauges.