Official NBS 4.3v6 to GEN 3 V8 swap Guide

[Selbyvince]

yeah ill have to look into it, nelson did my tuning.

what kind of MPG's are youll getting? Im getting right around 13 in town and on the highway. I did the daily driving tune with nelson, i have 3.73s, and only mods are the long tubes, o/r y pipe, and a gibson catback with and a k&n intake. I do have 33" mud tires on 18s, but i put this same setup on all my trucks and none of them got this bad of gas millage. And my last 3 trucks were crew cabs with the 5.3. Thinking if its going to be this bad im just going to have them put the performance tune in it and do the cam swap like i wanted to initially. The truck runs good, but doesnt feel like it has the power it should. Even a 2nd gear pull isnt all that impressive. Only code i have is a lean code. Im still using my v6 MAF sensor, and was told thats whats doing it.

Also, was your RPM gauge correct after the swap? Mine definantly is not. It reads 500-1000 higher then what i really have. What about cruise control? What kind of wiring do i have to do to get that to work again?

[zebra]

i typically get about 14 all in-town & about 16-17 if it's 75% highway @ 60-65mph. that's with 33s on 16s, 3.73s, LTs, ORY, airaid intake. that's on a mid-grade tune (maybe .5mpg less than the 91 tune i had before). also consider i'm at 3500-4000' & we regularly have crazy wind (30kt+). in TX running 93, i'd see around 18mpg hwy @ 75. in FL with my 31s, i'd seen as high as 20.

if anything, i'd get the A:F doped out first before making any other decisions... not that a cam wouldn't help anyway
my tach reads right - it didn't the very first time, but that was because i did the math & figured out Jesse programmed 4.10s instead.
no cruise in my truck.

maybe some other guys could chime in with their results

[Selbyvince]

hmmm, wonder why mine is so low then. Ill have to get my tuning checked for sure. Im in texas so 93 is everywhere, but with the prices of gas these days i went the cheap route to save a few bucks at the pump and did the 87 oct. tune. Not sure what the deal is with the rpm gauge then if yours reads right, maybe they messed up with my gears as well. Ill shoot erica an email about it tomorrow. Thanks for the replies, and yeah if anyone knows the fix for the cruise id like to hear it, i pulled some wiring diagrams up and printed them out, im sure i can do some work with the wiring and get it to work, just didnt know if there was an eaiser fix. Didnt realize how nice it was until it didnt work anymore lol.

If i move some wiring around and get it to work ill post it up here for others that may be seeing the same problem.

[BrockGrimes]

Ok maybe I missed it, but maybe someone can help.

I have an 03 silverado 1500 2wd 4.3 v6 with a cable throttle.
What motor options do I have?

Use any 6.0 and swap in an 02 and earlier harness and computer? and use a cable throttlebody?

Can the stock v6 automatic tranny be built up to handle the 6.0 or would it be better to swap the 6.0 and auto together?

[Selbyvince]

Ok maybe I missed it, but maybe someone can help.

I have an 03 silverado 1500 2wd 4.3 v6 with a cable throttle.
What motor options do I have?

Use any 6.0 and swap in an 02 and earlier harness and computer? and use a cable throttlebody?

Can the stock v6 automatic tranny be built up to handle the 6.0 or would it be better to swap the 6.0 and auto together?

You can use any 03-07 motor (4.8,5.3,6.0). You will have to convert over to dbw. (Very simple) You will use the wiring harness for the motor you buy, and you can get with a tuner and have them flash your computer to work with the motor.
IMO, the trans should be fine to start off with unless your doing something crazy with the motor.

[BrockGrimes]

So complete turn key 03-07 engine, and harness, and flash my v6 comp with my vin for the new engine.
What about the DBW and gas pedal? pull that from the doner as well, if possible?

Also read the 03 is a PITA, why was it an odd year/transition?

[Selbyvince]

So complete turn key 03-07 engine, and harness, and flash my v6 comp with my vin for the new engine.
What about the DBW and gas pedal? pull that from the doner as well, if possible?

Yes, they will have to alter your vin in the tune so that the computer knows it's a v8. But for the most part yes. Yeah you'll need the tac module which is mounted where your cruise control module is on your truck (if you have cruise). The wire going to the pedal, and the pedal itself. Nothing to changing all that out. Fun part is going to be finding the correct frame mounts. I went through 3 different sets before I found the ones that made my motor line up. And even then they were mix matched.