Official NBS 4.3v6 to GEN 3 V8 swap Guide

[Katana]

My silverado had only one fuel line going to motor. I think I might have to find a return line from a v8 setup

[Selbyvince]

My silverado had only one fuel line going to motor. I think I might have to find a return line from a v8 setup

If your truck doesn't have a return line, all you need to do is swap your fuel rail setup to a returnless. My motor came with a return style fuel rail, all I had to do was buy some returnless fuel rails off ebay and swap them out. Youll either have 2 hard lines coming from your tank or 3. If you have 2 your truck is returnless (feed, EVAP) and you need a returnless fuel rail from a v8 truck, or youll have 3 lines coming from the tank which means you have a return style. (feed, return, Evap)

[Gemini]

If your truck has a return setup and the motor is returnless you can also run a filter/regulator from the C5 corvettes. I used a WIX 33737 it's $40 from Summit and has an internal regulator thats set at 58#.

[OkieLSaddict]

I just completed the swap in my 2002 swb GMC Sierra, 4.3 to 5.3, started first try after priming with no plug wires on, runs smoothly, no codes, cruise works, only problem is the torque converter isn't locking up, no overdrive... Did I miss something? I've read every post...

[Ls_titch]

Hey I have some questions I'm in the middle of a swap I got my 4.3 out an the 5.3 getting a few touch ups my truck is a 2001 Silverado 4.3 I'm going to 06 5.3 an I have the harness an throttle peddle for the 06, I have ordered all the fittings for the fuel lines in there any thing electrical I need to swap in the fuse box an, do I need to swap any thing for my cruise control ? Thanks for the input

[Gemini]

My advice would be to get a v8 harness for your 01 and keep the drive by cable peddle. It's more trouble than it's worth to switch to DBW. If you get a 99-02 harness and throttle body, everything will plug in and run fine without making any changes to the fuse box or BCM. If you do decide to run the older harness you will need a new oil pressure sending unit. Part number ACDELCO d1818a. 50 dollars on amazon.

[Ls_titch]

My advice would be to get a v8 harness for your 01 and keep the drive by cable peddle. It's more trouble than it's worth to switch to DBW. If you get a 99-02 harness and throttle body, everything will plug in and run fine without making any changes to the fuse box or BCM. If you do decide to run the older harness you will need a new oil pressure sending unit. Part number ACDELCO d1818a. 50 dollars on amazon.

if I keep the 06 engine harness what electrical stuff would I need to switch I'm getting ready to drop the engine in this week end an would you happen to know what size the fuel feed line is on the 06 engine it is a Returnless style

[Lilredchev53]

I have my swap all done except I'm getting the start and immediate die. I've read threw the whole thread and it seems I need to do pcm flash to eliminate VATS. Is this correct? I've tried key on for 10 minutes then off and so on with no luck.

[Customtruckbuilder]

Has anyone used, or can confirm that these fittings will work for the fuel. I don't want to cut off my fuel lines.
https://m.summitracing.com/parts/rus-640820
https://m.summitracing.com/parts/ear...ENwxoCrn7w_wcB

[Jtburpo]

I have been researching swapping my 2007 classic 4.3 out for a 5.3. It is currently a DBC system. I haven't found clear answers for the correct engine and wiring harness. What is the correct year engine and wiring harness I should buy?