4.3l to 6.0

[Nitz45]

I am looking to swap a LQ9 into my 03 silverado 1500 5 spd short bed does anyone know where i can pickup a complete swap (wire harness, PCM) and what would be a good option for a trans that is still manual 5spd 6spd either is fine. also any pointers for my future project are greatly appreciated

[Frenchy]

03 is a pain in the ass year. Go to a junkyard, find another 03. You will need, engine, harness, accessory drive, all hoses, mounts (frame side), gas pedal, TAC module, harness from between pedal to TAC module. You have to go DBW, do not try to keep DBC. V6 PCM will work, just needs to be reprogrammed.

I swapped my '06 the stock 5speed is holding fine for now. Best option is a T-56 from an F-Body or GTO. There is quite a few threads on this already.

[Nitz45]

i have been looking through here and PT.net have found alot of useful info im still cloudy on the fuel lines alot of ppl just say to buy some flex hose

[Nitz45]

also what will it take to install the T56 and will there be any problems

[Frenchy]

Since you already have a 5 speed the t56 is just a simple trans swap & a new hole in the floor for the shifter, unless you get a relocation kit that moves it almost as far forward as factory.

My fuel lines (well line, my trucks returnless) I cut it just before it bends at the top of the firewall and put a compression fitting on it. Then ran a braided stainless -6 line to the fuel rail. Your truck is a return setup. 3/8 supply, 5/16 return.

[00shortbox]

I did a LS6 swap in my 2000 with the 5 speed, still not complete yet due to starter clearance issues. Gonna finish it in the spring. I used a 2001 2wd truck harness, couldn't find a 5 speed harness so I just got the auto. Only thing I had to do was jump the 2 wires at the park neutral switch connector so it'd start with the key.

[Frenchy]

Shaun all the wires are there for the clutch switch, I plugged my auto harness in and it worked like factory. Just had to splice on the reverse light pigtail from the 5speed and that's all I did to my harness.

[00shortbox]

My truck wouldn't start, it'd act like an automatic in gear trying to start. The clutch switch is obviously wired in parallel in my harness because as soon as I jumped those wires together it worked normal like a regular manual truck. I still have to wire in the reverse light switch.

[Botlfed]

You can plug in the auto harness and put the selector in neutral and it should work, don't you gotta buy a 4.8 liter flywheel ?