very ls newbe. please help advise opinions options?

[travlinman]

Hey guys I'm very new to this ls swap thing (like last week). I have a 91 r -30 crew cab dually with a tbi 454/700r4 combo. Power windows/locks cruise etc... Motor is toast was ran without oil. So I have a opportunity to get a 04 4x4 suburban with a 5.3 4l60e delivered to me for 650. Would love to swap everything including fuel tank and lines. How simple is this swap or how can I make it simple with the parts on hand.? Figure motor and computer harness but how much of it? All underhood wiring including fuse box?
Will I be able to use my stock cluster? Need gas pedal? I really like the idea of the rear tank and since I have to replace the tanks anyways why not? The tanks were drained when the motor went and caps were left off so I'm sure there's moisture in them. Can I just extended my current pump harness to the new rear tank?
Can I incorporate the new computer harness and keep all my power and cruise inside? Can I keep my 700r4 since the 4l60e is a 4x4 with transfer?
Overwhelming. ..
Any advice or opinions on my options would be very helpful
Thanks

[BR3W CITY]

This early in your swap, I'd go back and take a look through some of the builds and FAQ. Most of what you need has been covered, in more detail than I can easily type here at one time.

Make sure to get the DBW pedal, and TAC module to go with the truck. It'll match the TB thats on it and make life easier setting up the throttle system.

The swap, at its core, isn't much harder than a regular old engine replacement. Most parts bolt in with the help of a few simple aftermarket pieces. You can save the "scary parts" by having a pro make the swap harness for the engine/trans (limits your physically wiring to 4-ish wires to run). Your cruise control will not work with DBW. You can keep the buttons for it and use them to control the DBW cruise (which the computer controls), but the physically cruise box and cables won't transfer.

Its possible to keep the 700r4, and many have done so. You lose out on the computer control for lockup, and you have to use a workaround bracket for the TV cable.

[truckdude239]

Also you can keep your stock tank and use an ac delco ep381 fuel pump i side the tank

[travlinman]

Thanks Br3w but I did search some and didn't see anything really close to my truck situation being mine is a 91 r-30 last year square and already tbi computer controlled.my truck kinda falls into a grey zone with parts.
I have briefly seen a few use the 700r4 but didn't read into it fully.
My main questions were about swapping the newer tank and lines and using the new computer to control that or the old one. How much an I keeping or replacing with the new computer and what all I need to take off the donor truck.
I need the peel and line and tac module. Do I need the underhood harness? Fues box etc...or just what's under dash? Will that newer harness plug into my older dash?
any where u can point me to a thread I haven't found or info I can use would be appreciated

[BR3W CITY]

Originally Posted by travlinman

Thanks Br3w but I did search some and didn't see anything really close to my truck situation being mine is a 91 r-30 last year square and already tbi computer controlled.my truck kinda falls into a grey zone with parts.

Don't look at it from the mindset of "following instructions", by finding someone thats done your exact swap. Instead, consider that every build and info thread, contains information that will help you execute the swap. There are hundreds of possible configurations; best thing is to understand how the LS systems work, and it'll help you make your choices for the build.

I have briefly seen a few use the 700r4 but didn't read into it fully.

It will bolt up, but still needs a TV cable to set its pressure, and it can't be controlled by the ECM.

new computer to control that or the old one. How much an I keeping or replacing with the new computer and what all I need to take off the donor truck.

Your TBI computer will be a paperweight, and won't be able to run any systems on the new engine. You need to use the ECM that came with the motor. This is why I suggest getting the TAC module and pedal also (the TB, TAC,pedal and ECM need to all be from the same vehicle, or as close as possible).


I need the peel and line and tac module. Do I need the underhood harness? Fues box etc...or just what's under dash? Will that newer harness plug into my older dash?

You need the harness from the pedal to the TAC. You only need to take the underhood harness if you don't plan on having a swap harness made. I would strongly encourage you to have one made, as it will be preconfigured to run your engine and trans combo, and limit guesswork.

Your body wiring stays the same, but there are a few wires from the engine wiring that will need to be connected, such as the ignition, stop lamp for o/d locking, cruise control for Dbw if you want to set it up etc.

any where u can point me to a thread I haven't found or info I can use would be appreciated

lt1swap.com has huge wiring and pinout guides for the LS engines, as well as other stuff.
the "search this thread" function (not the google search at the top) will let you search just the LS section and refine what your looking for. Yes, it might take a few evenings of digging to get it all, but its all there.

[NorCalAnthony]

Doing the LS swap on your '91 isn't really any different than all the other square body swaps out there with the exception that you'll already have a lot of the things that other people have to piece together like baffled fuel tanks, electric speedo equipped cluster, VSS equipped transfer case (if 4wd), etc. Lots of options out there for harnesses and adapters and anything made for a square body should work just fine. Like somebody already pointed out, '91 was the first year of the 4l60 and 4l80 (no "e") and if your truck came with the 454 from the factory it should also have the heavier duty 4l80 trans.

One thing that might be a problem for you is I see you're in the bay area in CA (I'm up by Sacramento). Is your truck registered as a diesel by chance or do you still have to smog it? If you still have to smog it then your swap just got a lot more complicated lol. It's definitely still possible but things get way more complicated because you'll have to keep not only all of the emissions equipment but also the evap system and have everything installed somehow and also functional for the smog ref inspections/certification. You'll need to run the stock exhaust manifolds (or ones off another LS vehicle like the TBSS or Camaro), stock cats or CARB certified aftermarket ones, all the O2 sensors, fuel pressure sensor, purge solenoid, charcoal canister, etc. Basically everything the newer vehicle had for those systems has to be transferred over to your truck to be legal. It's not the end of the world but it's definitely more than most guys have to deal with when doing these swaps. I wound up buying a complete wrecked donor vehicle for my swap just so I'll have everything I need when it comes time to do my swap lol.

[clinebarger]

The 4L80E has always been electronic, The 4L80 is a myth/unicorn that doesn't exist. The TH400 had a name change to a 3L80 in '87 along with the 700R4 becoming a 4L60.

[NorCalAnthony]

I haven't seen one without the "e" personally so you could be right but I've read in several places that the early ones didn't have that designation until '93 or something along those lines. I've honestly never heard of a th400 being called a 3l80 but my '89 Blazer still has a 700r4 in it so I know there wasn't a name change by then for that trans at least. Either way the OP wouldn't have a 700r4 behind his big block unless it was swapped in at some point along the way.

[travlinman]

Thanks truckdude. I was thinking I need to replace the tanks anyways due to being open to moisture/rust for a few years I didn't want going into a new motor so why not move it back and use the newer tank and pump? If it's that much of a hassle I can just replace 1 tank and use that newer pump.

[clinebarger]

A '91 R/V-30 should have a 4L80E, First year for the 4L80E, Last year for square body trucks. No 1 ton truck came with a 700R4 from the factory.

[Matt Cramer]

The 4L80 designation sometimes pops up, but there's no hydraulically shifted 4L80E variant equivalent to the 700R4.

[BR3W CITY]

I stopped arguing with Cline on transmissions when I realized he built them (I mean who else would have the Hydra-Matic logo as his avatar?)

[NorCalAnthony]

Originally Posted by BR3W CITY

I stopped arguing with Cline on transmissions when I realized he built them (I mean who else would have the Hydra-Matic logo as his avatar?)

Good point I stopped arguing because I know how to read a name plate and didn't want to take any more focus away from the OP's actual questions.

[travlinman]

Ok..well thanks guys. Norcal I'm actually in stockton now moved from San jose. Also do have a no smog title so I'm not concerned about that.
I have access to the whole vehicle so getting what I need isn't really a problem. I'm going to get the motor and all of the wiring harness from under hood to under dash. Tac module.gas pedal and exhaust with o2 sensors. Everything electrical just incase I need something later on as I try and wrap my head around the swap . would like to run the suburban tank an lines but just might convert it to a single pass side tank and swap in a new pump. I will check this weekend on what exact trans it has and go from there. Would be great if it has a newer 4l60e or 4l80e trans.

[NorCalAnthony]

Originally Posted by travlinman

Ok..well thanks guys. Norcal I'm actually in stockton now moved from San jose. Also do have a no smog title so I'm not concerned about that.
I have access to the whole vehicle so getting what I need isn't really a problem. I'm going to get the motor and all of the wiring harness from under hood to under dash. Tac module.gas pedal and exhaust with o2 sensors. Everything electrical just incase I need something later on as I try and wrap my head around the swap . would like to run the suburban tank an lines but just might convert it to a single pass side tank and swap in a new pump. I will check this weekend on what exact trans it has and go from there. Would be great if it has a newer 4l60e or 4l80e trans.

Nice dude. I wish my K5 had a no smog title lol. What kind of budget are you working with for the swap? As in, are you trying to stay on the cheaper side and do as much work yourself as you can or are you going to be buying a lot of the aftermarket pieces to make things easier? If you're looking for the easy way I'd get a swap harness made and check out some of the swap systems out the like this new one from Hooker: http://ls1tech.com/forums/conversion...m-preview.html If you're trying to do as much work yourself as you can lt1swap.com is a great reference for making stand alone harnesses (as well as other LS wiring information) and also has a very budget friendly re-flashing service for your PCM.

[travlinman]

I'm on the way way cheap side of things as in i eas planning on a several year project. Most if not all the work I will be doing. That's y I'm trying to figure out everything I needed or could get from the donor truck. I don't have any extra to all aftermarket parts..I also have a 78 crew with a running drivable 454/th400 combo I thought about swapping in with fuel tanks and all since there different with tbi and power pumps. But than I was having to rewire anyways taking out the computer for everything and going back to a simpler combo.
Than that got me thinking if I'm rewiring anyways see what a ls swap is all about. Found a running $500motor/harness tanks combo or a 650 complete donor vehicle delivered to me and can take all that I need. Another snowball that I hadn't even really thought about. Since my 91 is in a grey area between years of trucks and body styles it's a mix of parts and new computerized stuff already.

[BigDan3131]

Another thing to think about is putting that little motor and trans in a big crew cab dually. I would look for a 6.0 with the 4L80E instead unless you had plans to build that 5.3 up quite a bit but then your mileage will still be just okay.

[travlinman]

Big dan. Thought about it but there abit harder to find in a wrecked truck unless I just buy a motor outright from somewhere and I don't have a budget for that. This would mainly be a daily driver weekend family type cruiser not any type of tow pig so it should be enough.

[travlinman]

Well with the help of clinebarger and looking over my glove box sticker I have a MT1 code means it did come with a 4L80E trans. So I got under the truck to get a pic and have to post that so u can get a verification on that and it hasn't been changed.
Another question. Can I run my power steering pump since I have a hydro boost system?

[BR3W CITY]

The HB pump has 3 lines going to it, the regular one only has one feed and one return. Did you want to run the hydro braking, or just use the pump? You can totally use an HB pump on a non-hb setup by T'ing the extra line.

[MalibuSSwagon]

I am working on a 5.3L swap on my 86 C10 currently, going to use the underhood fuse block and adapt it to the C10's dash harness. I've been using lt1swap for the guides and diagrams

http://lt1swap.com/2000harness.htm

http://lt1swap.com/underhoodfuseblock.htm

I'll let you now how it turns out.

[travlinman]

Br3w..would like to keep the system intact and use steering and braking if possible.
I should be getting my donor suburban today.
Hopefully get it stripped in the next week or 2 and cleaned up enough to drop in.
With trimming down the harness or a stand alone harness how many of the senor are being used and how will I know if something goes bad? Still need o2's correct?
I've been over the ls1 tech forms trying to learn what I can but that site is not real organized

[BR3W CITY]

Originally Posted by travlinman

Br3w..would like to keep the system intact and use steering and braking if possible.

I have some pictures of my setup in my build. All thats really required is getting the HB unit and master bolted to the firewall, modding the pedal linkage to be the right stroke, and hooking up all the lines. It seems like a bunch of folks (myself included) get over-touchy steering from lack of residual pressure valves. It still works fine, its just 1-finger cadillac steering. We're working on figuring out exactly what the problem is, but the braking aspect works great from the onset.

I did an internal rebuild on mine, which isn't hard, but also not needed on most units.


I don't like the stock style 02 sensors because of the different plugs and the cost to replace them. I' just rewire with the Bosch 13444, which is the cheapest and easiest-to-wire heated 02. You'll want to have them unless you switch to SD tuning (ditching the MAF and 02's), and running a wideband/logging. That way is much more time and tune-intensive but makes a touch more power and is often how the sandrail/boat/pull truck setups are built.

[boostedc10]

Travlinman most of the standard sensors are left alone in the harness. What you eliminate is typically down stream o2s, the EVAP stuff and if no a/c that can go to. The link Br3w shared from LT1 swap also shows you have to wire in an obd port and a check engine light so you can make sure everything is ok and check for codes.

Most people keep at least the upstream o2s so they can put the vehicle into closed loop and let the ecm make fuel corrections as needed.

Running without them or just a wideband eliminates this feature.

[boostedc10]

You want the O2 with sd tuning too. It makes no sense for a street car to run open loop unless you tune yourself and even then I still don't see the point in leaving it open.