1990 C1500 LQ9 Swap Questions, From Alaska.

Greetings fellow swappers... I was wondering if some of you would be kind enough to supply me with a little more information for a swap I'm hoping to complete in the near future. The truck is a 1990 C1500 that has a full air suspension, and will be body dropped after the swap. I'm hoping to swap my tired and worn 350tbi to a 6.0L LQ9 and wanted some details on the proper route to take. I'm not looking for huge power, I won't be doing any FI, and I'm interested in keeping the stock 700r4 (Monster Transmission Built).

Now my questions relate to the DBW/DBC throttle body... is it necessary to maintain DBC on the 2006+ engines, or can I convert to DBC by changing the TB?

I read on the forum that a majority of people that swapped over use mounts that move the engine 1" back to maintain close to stock positioning of the new LS motor, does this also go for the LQ9?

As for the harness I'll most likely purchase a custom piece from Nelson Performance... The price is just too good to be true, and I'd like to put the factory ECU in the front dash to hide it.

Any tips and tricks to aid/simplify the swap would be great, and a total parts suggestion list would be awesome!!!

Over 100 views and no love..

I know very little because I am in the process myself. I do know that one inch setback mounts work on the v8 frame mounts in your body style truck. That does work with all LS engines. I also know that you will need a ls1 Camaro oil pan to clear the bottom of your cross member in that you are lowered. The stock pan will hang below the crossmember by a fair amount, from what I understand it is about 2 inches. I bought a complete 2000 Silverado to use as a parts truck so I couldn't tell you about the drive by cable versus drive by wire. I believe the 6 liter uses a flat flexplate the does not require the spacer commonly used in the 5.3 to the earlier 700r4 or 4L60E swaps. Take all of this with a grain of salt and verify it for yourself because like I have said I am in the process of research myself.

I used the dirty dingo adjustable mounts and measured where my 350 was mounted and set the dingo mounts on the ls motor in the same location. Everything from there lined up the same as it was with the 350. If the intake manifold has a 3 bolt DBW throttle body you can bolt up the dbc TB . If the TB is a 4 bolt you will need an adapter. You also have to make sure if you go dbc that the pcm you use is compatible. The pcm has to have the drivers for the dbc setup.

^^ yup

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Originally Posted by gagliano7

I used the dirty dingo adjustable mounts and measured where my 350 was mounted and set the dingo mounts on the ls motor in the same location. Everything from there lined up the same as it was with the 350. If the intake manifold has a 3 bolt DBW throttle body you can bolt up the dbc TB . If the TB is a 4 bolt you will need an adapter. You also have to make sure if you go dbc that the pcm you use is compatible. The pcm has to have the drivers for the dbc setup.

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After doing some research I figured it would be easier to swap the pedal and related components into the truck, after searching around on ebay I figure the $100 or so dollars for the pedal, and the $100 or so for the LS1 TV kit would make the swap affordable and simple.

Skylark, Thanks for the info on the oil pan. The truck will be traditional body dropped after the swap so the more space the better.

Anyone have a part number for a radiator bracket for this year truck? I'm using E-Fans at the moment.

Do you already have the DBW pedal and TAC module? If so it's a nice swap and makes the cruise control easy to hook up and works really well. I'm glad I stayed with dbw and wouldn't change it for anything. But if you don't already have the parts then maybe dbc would be easier. Just be sure the computer you use is compatible with the throttle body you go with.

I was just going to purchase a DBW pedal and TAC off ebay, they're cheap enough that the point of going cable isn't really worth it.

I was also debating on getting a built 4l80e to go along with it.

Be sure they are compatible with each other. Not all dbw parts are the same. If you could get them all from the same vehicle and one that matches your ECM it would make life easier.
http://www.lt1swap.com/dbw.htm

Im not sure the dbw tb is going to jive with the 700r4. I dont think youll have anyway to actuate the tv linkage. I have an lq9 in a 90 454ss, as others said, 1" setback mounts are what you need. I sold off all the DBW stuff and picked up a cable harness/pcm/tb. I reworked the stock harness and the pcm in is in the dash in the stock location. You are going to want the f-body pan. I have the gmpp hot rod/h3 pan and its still about an inch below the crossmember.

Thanks for the reply, I'm still debating on which motor to purchase for the swap... The more I look at it the older DBC setup looks easier, but the DBW seem more through of an installation.

I'm curious, and hopefully you fellas can make some suggestions...

In Alaska we have plentiful access to 4wd transmissions usually leaving 2wd's hard to find. Can anyone reccomend a shop that can sell me a transmission that would mate well with a 6.0 out of a 2002 Chevrolet 1500? The more I think about it I'd like something a little more current than what's presently in the truck.

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Originally Posted by 12thstreetjunkman

Im not sure the dbw tb is going to jive with the 700r4. I dont think youll have anyway to actuate the tv linkage. I have an lq9 in a 90 454ss, as others said, 1" setback mounts are what you need. I sold off all the DBW stuff and picked up a cable harness/pcm/tb. I reworked the stock harness and the pcm in is in the dash in the stock location. You are going to want the f-body pan. I have the gmpp hot rod/h3 pan and its still about an inch below the crossmember.

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Alright fellas, I finally had time to look at some motors, figure things out... and the C1500's stock tbi 350 is about to bite the bullet.

I found a decent looking lq9 out of a 2005 Escalade, for a round $1400. I'm having a heck of a time sourcing a transmission for it, and I'm thinking it would be easier to purchase a 4l80 from Jakes Performance, I think their stage 2 4l802a will do the trick, and the cost isn't something out of this world.

Now with these two major components does anyone foresee any trouble finishing the swap from the tbi? I've hit the point where I'm just about desperate to swap the motor and get the truck running right so I can enjoy it. I absolutely hate how the truck drives at the moment. Swapping to a cable throttle body is going to happen, and the 4l80 is going to be my transmission of choice. Motor and trans will be left stock, I just want to get this thing running after... and I've already got a huge project on my hands at the moment.

well like mentioned, no matter which TB you go with, you have to get the correct pcm. i believe some pcm's only control dbc, some only for dbw, and some do both. need to use the s/n to find out. not sure why so many people go with the dbc. dbw is not hard to install at all. just bolt the pedal in place, plug in and your good to go. makes cruise easy. hardest part is bending the pedal to fit around the trans tunnel. but hey, whatever floats your boat. and obviously the computer needs to be flashed for whatever mods you decide to do.

kewljay, thanks for the reply. When I get home I'm going to take a trip to the yard and see what motors are available. From there I should know what I'm going to be looking at for an ECU and I'm going to definitely be ordering a 4l80 in the future.

Thanks everyone for keeping this forum updated with information, it sure is helpful!

Finally made some decisions on an engine and transmission setup. Looked around at the salvage yards and found it difficult to source a 6.0 for under $1600, decided to go with a 5.3 out of a 2000 Silverado, and mate that to a 4l80e from a 1999 Chevy Express Van 2500. I also found a plethora of ECU's from the same yard for under $100 dollars... So it looks like I'll start stockpiling parts for the swap into my bagged 1990 C1500 sooner than I thought.

Ordered the following parts:
Schoenfeld headers ls to truck swap style.
CTS-V oil pan, pickup, dipstick and tube.
Carshop Inc 1" setback mounts off ebay.
HP-343 Fuel Pump kit, and adapter fittings ordered.

I'll also be picking up a 5.3 and 4l80e from a recycler in the coming weeks.

Engine harness will be coming from Nelson Performance.


Can someone help me out with a clear defintion of whats needed for the fuel system?

I'm going to order the HFP-343 fuel pump kit
what else do I need to get fuel system working properly? Some say use a corvette fiter regulator, others use other parts...


And I'm going with some -6an fittings for the transmission lines so I can run braided stainless.
http://www.sweetperformance.com/prod...ory&cat_id=241

Thanks for your help!

I'm also looking at the Comp Cams 1449121 or the 224/232 cam, upgraded 7.4"x5/16" pushrods with 99831 beehive springs... I'll reuse the retainers.

Update,

A different recycler has a 80K 6.0 out of a 2006 Denali, Matching ECU, and a 1999 4l80e on hand... I'll be picking it all up this Saturday!

Ok fellas, I picked up a 2002 6.0 out of a Yukon Denali, and a 1999 4l80e out of a Express Van, and A ECU with a service number of 12200411. The TB is DBW, and the yard didn't have the TAC module or pedal available. Does anyone know where I could get those parts so I can start working with Nelson on a harness?

Update:

Ordered the following parts off ebay since my local salvage areas don't carry them.

http://www.ebay.com/itm/201243003716...%3AMEBIDX%3AIT
http://www.ebay.com/itm/181395138675...%3AMEBIDX%3AIT
http://www.ebay.com/itm/251672171743...%3AMEBIDX%3AIT

I think this should be about all I need correct?