i know you are sick of newbies asking but I cant find what I am really looking for. I have an 01 sierra 1500 extended cab. I am in the process of installing an lq4/4l80 pullout from a 04 2500.

Seems like there are a few minor differences in the two harnesses. looks like the primary o2 sensor plugs are different and the cooler lines. maybe some other things I cant remember right now.

Can someone point me out a good thread(s) to go over. Seems like most people are just swapping long blocks.

Do these computers have a vats system? Will i run into any interface problems with the lq4 harness and ecu with my 1500?

I have 243 heads and a ls6 cam in my 5.3, what will the compression on the lq4 be with 243 heads if I decide to swap them?

thanks for pointing me in the right direction.. time to let the neighbors get some sleep.

 

your compression on the lq4 will be 9.5.1, right now on the 5.3 your at 9.0.1 or close if your using the 243 heads built for a 5.7 or 6.0

if there the newer 243 heads on the 07 up trucks then your at 9.5.1 or close, and if you put them on a 6.0 then it would go up maybe to 10.0.1

the trans and harness are different look at the sponser list over here--------------->

finish line trans or maybe a few others have what you need you will also need a new bracket to hold trans.

https://www.performancetrucks.net/fo...highlight=4l80


your search at the top is your friend heheee, just type in 4l80 and it pullls up alot good luck.

 

What i did.. and i suggest this..

Wiring harness is a easy one.. Swap the White and Brown wire on the transmisison connector. Add 2 wires to the PCM from the Front VSS.

https://www.performancetrucks.net/fo...d.php?t=413157


Remove intake manifold off of LQ4, Replace it with your current Intake.
Swap any Sensors to fit your current Harness (only sensor i had to swap was the oil pressure).

Modify your crossmember or buy the conversion xmember.

Get it tuned for the 6.0/80E.

Theres no point in tryin to use the 6.0/80E harness, just use your current one.

PM me if you need some more help, this is a easy swap.
I replaced my 2000 5.3/60E with a 2004 LQ4/80E.