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

[EagleChief]

Alright - So looking for any and all input. Wife and I decided to do an LS swap in my '71. The current motor is from an '88 Suburban and has issues. It's tired, worn out, has blow by, uses coolant, loses coolant, smokes, stinks, and just plain sucks.

This truck is going to my son, eventually (he's 4), so I want it to last and be good to go for him when he starts driving. Plus, I want to be able to just jump in, hit the key, and take off when I want.

Now, to my issue... I'm trying to read and learn and make a spreadsheet of what I'm going to need to make the swap happen. Problem is, I've never attempted a engine swap before, let alone going to a modern engine. I can turn a wrench, and like doing my own work if I can (with guidance and help and YouTube). But this is going to be the largest thing I've ever done. At the same time, I've been getting quotes from a few places on how much it would cost to have it done due to time constraints (I have 2 kids, 4 and 2, with another one due at the end of the year.

I know I need a '99 and up 5.3 and a 4l60e transmission. I have a local salvage that has the setup - 2004 with 120k miles and it comes with everything. It's still in the truck. It has the accessories, harness, computer, transmission, and it has a 45 day warranty. They want $1750 for it. Is that a decent price? My issue, if I can hear it run, I don't really know what I'm listening for - other than knocks or taps. But, if I hear/don't hear those, I don't know how to diagnose the motor if it's good or bad - other than the common sense type stuff. I'm not even sure if they are able to start it up for me. I just briefly talked to them on the phone a couple of days ago.

That's the main question. The next question - does someone have a comprehensive list of what all I'm going to need to make this happen? Cooling system, fuel system, engine/transmission, exhaust, and "extras" are my sub-divided systems in my spreadsheet I'm trying to make.

I did find a thread on here that had a cost breakdown of member's builds. I saved a couple of those builds, but being completely new to this, it's just mumbo-jumbo right now, until I fully get into doing this.

Now, I know there are a "crap-ton" of threads on this. But, I've been reading what I can and it just confuses the heck out of me. Mainly because I see lots of different inputs and ways to do it. Now, I know I'm inviting that here. But, I need a good starting point. Even down to who has the engine mounts that will work (currently have Dirty Dingo engine mounts on my list).

Thanks for the help and guidance to this new guy.

[Woodnears]

In doing this a couple times myself i will give you one suggestion that i think will prove to be a fairly common recommendation. Buy yourself a quality wiring harness! I prefer PSI harnesses but that is my preference. A handful of connections and you have a running engine. Its really not a hard process and something that is not worth paying someone to do if you have a little time hear and there you can do this!
Can you give us some details about the current truck? Stock gas tank? stock radiator? lowered? lifted? How is the current wiring in the truck? is it stock wiring?

[mongocanfly]

I felt the same way when I did my 1st one...but I was amazed at how everything just fell in place..I did it before I had this site to help, so my guidance mostly came from a speedshop..
1st thing on your list is the biggest..make sure you get a good running and working setup..
1750 is a decent price for a complete setup....zip codes greatly affect prices..
If you can hear it run , just look for smoke, listen for odd noises, put a code reader on it...
120k on a LS isnt bad..
That's not much of a warranty considering your gonna eat most of that up with the install..
There are quite a few that have done the 68-72s so they can offer better advice..
On mine I used the ol Ebay adapters for motor mounts....lots use the DD so they must be pretty good
Your stock radiator is plenty for the engine, you'll just have to plumb it up..
Decide if you want elec fan or mech
If you get a dbw engine ,make sure you get the pedal and module
Make sure you get the ecm
Theres gonna be some hurdles to cross with the install..not sure about the trans xmember..
Driveshaft may need some work
shifter linkage connecting
On the fuel system you'll need to go high pressure..its been done on incab, but I'd get rid of the incab tank, if that's what you have..
you'll need all high pressure fuel lines..depending on the engine it could be a return rail or returnless rail..cross that bridge when you get to it..
On the exhaust...it depends if you want manifolds or headers...either way you'll have a trip to the muffler shop.
I hate wiring , so I always have bought my harnesses...its nice to just plug it in and go..
I also have used psi, but my next one will be a BP harness..
The BP has a longer main harness allowing the ecm to be mounted under the seat..
Another hurdle is do you have a shop to work out of..
Another set of hands is nice to have also...but I've done all mine by myself..
You'll need a engine hoist and a good basic tool set

[EagleChief]

I appreciate the feedback. I did have one suggestion from a co-worker buddy to use a Holley Terminator X computer and harness. The downside of that, it's about $1000. My accountant (wife) probably won't ok that type of expense, but, it's on my optional list.

Details of my truck:
sbc350 from an '88 Suburban (supposedly)
700r4 Transmission
3.73 Gears
Stock gas tank with a Holley external fuel pump under the cab
Free radiator from a '73 Camaro from my co-worker
Lowered 3.5" front, 5" back. All new suspension components

Current wiring is somewhat of a mess. It's been spliced I don't know how many times. Under the dash looks like a rats nest. Speedo doesn't work (not hooked up) I'm guessing due to the transmission swap in it. Temp gauge didn't work. Oil pressure didn't work. I now have a aftermarket gauge cluster to monitor those, and I use a GPS that came with the truck to monitor speed.

[mongocanfly]

Stay away from the Holley stuff..the LS stuff is more tha adequate..
You'll just have2have the ecm flashed
You can run a inline pump for the swap...but you'll need a return line on the tank..whether you use a Inline filter/reg or use a return rail system..you'll still need the return to tank..
The LS harness is freestanding...it only needs constant 12v, switch on 12v, and some grounds..
So its independent of the truck side..
Have no idea about the Camaro radiator
I would get the truck harness in good working order before you do the swap....thatll eliminate future headaches
A working speedo will require a convertor box or go to elec speedo

[mongocanfly]

The ECM will need to see water temp...it uses the sensor on the drivers head at the front..
For water temp gauge, most drill and tap the pass side head for a temp sender..
Oil pressure can come from the stock LS location...you'll need a metric to npt adapter

[EagleChief]

I'm looking at the PSI harness and BP harness now. I like that price a lot better.

I know I could save some money by using my existing transmission. But, if I can get a package deal, then I'll swap it out.

[mongocanfly]

4l60e is basically a 700r4 anyway ..but youd have issues with the 700r4 kickdown anyway..
you'll be better off with the 4l80...

Think about where you'll mount the ecm..the psi harness isnt long enough to put ecm under the seat..
You'll be limited to under dash or underhood..

[TrybalRage]

I kept a fairly complete partslist with prices and part numbers of what I used.

https://docs.google.com/spreadsheets...it?usp=sharing

Mine is an 85, so there will be differences, but most of the stuff would be the same.

If you're keeping the tune/motor stock, the stock ECM is fine. You can either do your own harness (www.lt1swap.com) or buy one. BP automotive gets a lot of good reviews, but there are others. Minimum you'll need to ECM flashed to remove the security stuff (VATS), I paid $75 to the LT1swap guy, but lots of places can do it.

If you're upgrading the motor, then the holley stuff is pretty sweet, supposedly self-tuning to a certain degree.

[LS short box]

I doubt your current in-line fuel pump will support the the 58 psi needed for the LS swap. I've used both internal and external fuel pumps for LS swaps. External Bosch 044 and internal Walbro 255. Buy from a known supplier so you don't get a knock off.
I like -6 line SS line and a C5 fuel pressure regulator. Buy Wix or Delco.
I always buy an aftermarket harness. I like Howell or Speartech.
If your original wiring harness is hacked I would redo with an aftermarket harness like Painless or American Auto wire. The LS computer and engine loves nice full 12 volt power and nice clean grounds. Also keep in mind the LS alternator puts out 2-3 times more than your stock alternator so it needs wiring to support that increased output.
I have a buddy running the 2002 Camaro radiator and fans. Works like a champ. Your harness supplier can supply the dual fan out puts and relays.
Good luck with the swap. Don't hesitate to ask questions.

[derotoreut]

I just finished my first LS swap. I did everything myself. Now granted mine was in a 70 K10 4X4. I used a 2000 5.3L 4L60E set up. A 4L80E is a stronger transmission, but for my case I did not want to have to modify front and rear driveshafts for the 4WD, so the 4L60E fit that bill. You can check out my build thread in the link below my signature.

I got my harness from Pacific Fabrication/Tilden Motorsports. I agree that buying the harness is the easiest way to go. I've heard good things from PSI & BP, but my next one I will use Howell.

I have a list of items that I used in my build thread. Hopefully that helps.

[truckdude239]

1750 is not bad make sure they give you the gas pedal and tac module as a matching set out of that truck!! I paid 1500 for the 2004 4.8l 4l60e with all power steering air tube pedal and tac module starter and harness.

[LS short box]

Again just my .02 if you move up to 2006? engine and trans or so you can get rid of the tach module and just run the the DBW pedal directly from the ECM. But if you do that there is one ecm for the engine and one for the trans. Not a big deal. All harness suppliers can do the swap.
The cool thing about a properly done LS swap is when you turn the key it just starts.

[EagleChief]

Whew! That's a lot of info in a short amount of time! But, I appreciate the help, fellas, and that's what I'm looking for! Thank you for all of the input.

The first 2 things that jump out at me: 1) what is the tac module? and 2) what is the VATS that I keep seeing pop up when people talk about the ECU?

I'm leaning towards buying a harness that is already done. That way, I can get rid of a bunch of the crap wiring that's in the truck now. I mean, I have a wire (I think the starter wire) that is spliced 3 different times between the firewall and down below the engine where I lose sight of it. It's purple coming out of the firewall, halfway across the firewall, it is spliced into a black wire, then down on the passenger side, it's cut and spliced into a red wire. Which, I know is "ok" as long as the wire gauge is correct and it's connected good, but, still... that's just trouble waiting to happen.

Is the '04 year a DBC or DBW? Also, I want to go ahead and start purchasing parts, but do I need to wait to see what motor I end up with? Or, can I get things like radiator, engine mounts ahead of time?

[ls1nova71]

The TAC is the Throttle Actuator Control module, it is what controls the DBW throttle body. VATS is Vehicle Anti-Theft System, it will need to be programmed out for the engine to start.

2004 will be a DBW engine if it came out of a truck, but vans were mostly DBC until 2007 or so.

You can buy parts like radiator and engine mounts without having the engine, but when buying an engine, if its DBW, be sure to get all the electronic parts, TAC, gas pedal PCM, etc. all from the same vehicle to avoid mismatch issues.

Here's a link to my green truck I did back in 2012. The prices are probably a little out of date, but will give you an idea on what all is involved. https://ls1tech.com/forums/conversio...71-c-10-a.html I do things in a somewhat unconventional way sometimes, so take that as you may.

[beaterku]

First off, you are going to love the LS. There are a lot of haters out there, but it is well worth the money. My suggestion, try to set a budget and keep to it. There are numerous rabbit holes you can go down along the way that get expensive (I got caught in a couple of them).

Shamless plug, I have a Youtube channel that document my build and LS swap. It's at https://www.youtube.com/rustywrenches

This forums is a great resource with lots of great information and people. If you feel like you are stuck somewhere, I can guarntee the answer is somewhere on these forums. Don't be afraid to ask questions, someone will answer them.

-Nick

[hounddogs!]

Confirming that lt1swap.com is a great info source too. I followed his videos to strip down the 2004 wiring. My '68 wiring is in pretty unmolested, so I didn't go the Painless route.

I kept the factory gas tank and the canister fuel filter on the pass frame rail. Mounted a Bosch 044 and 5 micron filter downstream of that. AN fittings added to the corners of the tank for feed, then used the factory feed pipe for a return line.

Stuff I remember in no particular order:
*Use GM O-rings on the injectors. I had a leak and some fiery excitement with Napa pieces.
*Moved the batt to the driver's side
*ECM mounted on the DS inner fender.
*Dirty Dingo motor mounts are foolproof.
*Make yourself a check engine light and diagnostic port (see lt1swap.com and others).
*ICT Billet has a good selection of metric adapters.
*Like others have said, get the ECM, TAC module, wiring and DBW pedal from the same donor.

We're here to help.

[MidLifer]

I don’t know if member 68fouronthefloor is still doing this but when I did my lq4/4l80e a few years ago he sold me a pre-stripped oem harness and ecm with vats and cats removed (cats = you also have to deprogram the downstream o2 sensors, since you won’t be putting catalytic converters in). Price was very reasonable and I have had no issues with the gm harness other than it isn’t as pretty as the aftermarket ones. lt1swap.com has great instructions about the relays you’ll need and how to graft the harness into existing wiring. Sounds like your in-cab harness is pretty hacked up so you may want to just rip it all out and start over. American Autowire has good harnesses (not ls harness but what you’d need for the rest of the truck) at competitive prices.

Other lessons learned:

I tried to keep the in-cab tank and put a high pressure pump in it. Because I had a return-type fuel rail, the gas running back into the tank caused a smell and the pump sounded like a dentist’s drill. I ended up getting a Boyd’s welding tank in back.

If you are going to use -AN type fuel line (the braided type) buy the Teflon lined type. Ethanol fuel will vaporize right through rubber fuel line, make your cab and garage smell and eventually rot it out.

Note that after you get the truck running you’ll want to have the ecu tuned to increase hp and perhaps tighten the shift map for more fun. Find a local tuner, I’ve heard the mail order jobs are variable in quality. Should cost about$400 the first time (that includes the software license) and $200 fof subsequent tunes if you want to keep fiddling.

Also if you want a more classic gas pedal feel you might want to switch out your air intake to a drive-by-cable one. The earlier LS engines had them and you can find them everywhere. Then you can keep your stock gas pedal and even the cable iirc.

Feel free to dm as you go through your project. There are tons of little tips and tricks and I can’t remember them all here.

My swap was by far the best thing I did for my truck. No more low vacuum stalls, better gas mileage, and starts up in all weather with one turn of the key. Oh yeah, and runs great on ethanol regular gas. No more paying up for premium.

[Warrens69GMC]

Sounds like a cool swap.

[jjzepplin]

I am not finished with my first swap but right in the middle I think. I would say that if you have the room, A complete donor vehicle will run you about the same or less than just the engine setup. Then you can hear it run and save money on a bunch of little crud. I was able to get the whole car, Sell the shell and related parts and the existing engine setup and ended up having money in my pocket and a known running setup for next to nothing but labor. I would check auctions for wrecked trucks or police setups. I am using the fuse box from the car as well so I can use the fans and radiator etc. Belt system parts can end up ruining your bank account too. Run as much stock stuff you can at first. You can always modify later. There are 3 "depths" of pulley systems. One for trucks, one for Camaros, and one for Vettes. Getting the whole shebang from a donor will save you big.

[LS short box]

On my LS swaps I use as many stock LS parts as possible so if there is a failure you can get the part at the local parts store. The non-stock spare part I keep in my road side repair kit is the aftermarket fuel pump. I never had to use one! If the engine is stock a mail order tune should work fine. I used Frost Tunes on a stock LS1 and it worked great. Check over on LS1tech for other mail order tuners. If the engine has a cam or other mods a chassis dyno tune is the best. If you buying an engine that has a ton miles on it and are considering rebuilt fuel injectors make sure they come known rebuilder. It's critical to a good tune the injectors are flowing at what they are rated at like on a LS1 they are 28.8 pounds. Again check over on LS1tech.

[Low Elco]

STOP RIGHT NOW and read all of the info in ls171nova's threads in his sig. Using the info in them, you can jump off from there and get as crazy as you want, but all the basics are there. It seems scary at first, but after you do one, you'll wonder what you were so afraid of and be looking for the next one. The factory computer is fine. There's lots of vids on how to cut down your harness or if you're a chicken like me, it's 6-700 for a good one. I use 150tunes.com, but psi or fuelinjectionconnection.com are good too. You'll love it, jump on in! Check the New heart thread in my sig for my foray into it. DISCLAIMER: I'm extremely lucky in that I live about 2 miles from ls171nova (Eric) and he apparently has the inexhaustible patience of a saint.

[EagleChief]

I appreciate all of the feedback! I know I'm ready to do it, it's just taking that first step off the ledge that gets me. I read through ls1nova's thread and derotoreut's thread. Impressive to say the least.

I'm still looking for a donor. I have thought about the idea of just buying a wrecked truck and swapping everything from that. My problem is storage - I'm already out of space at home. My other option is to keep it at my parents, which is about 20 minutes away. Still trying to decide if I want to do it, or have it done. Time and knowledge are my downfalls - although knowledge I know I can gain from here and by asking questions.

[mongocanfly]

You can pull everything you need from a donor and not have the need to keep the other vehicle..just be sure to get all the needed parts..

[EagleChief]

Just a quick update - No progress, but making record of what I'm doing...

Emailed a local shop that does tuning and makes custom harnesses (Prevatt Auto). They referred me to another mechanic that "does more LS swaps than any other shop in Tulsa. You'll be surprised at his prices". They have a working relationship on swaps and tuning it sounds like. Both really nice guys, and referred each other for LS swap needs.

Brad (mechanic) quoted me between $2600-$3000 in labor, and time frame of 1-2 months, depending on his workload. I asked about him supplying parts (I know where that leads), but I was just feeling him out. He said he hadn't had any motors in a couple of months. His last few customers have supplied everything. But, he has a guy that goes to auctions and he'd (Brad) would have him keep an eye out for donor vehicles and let me know.

That's all I have for now. Have a good day!