4.3 to V8 swap?

[texasranger96]

I have read the swap thread thoroughly and I have a few more questions, I am aquiring a Sierra regualar cab 2wd truck it is about as basic as you can get it. I have been told the V6 gets over 400 miles to the tank and I have had two of these trucks with V8's and never seen that, so if I do the swap I want to keep the mpg so I will try avoid the truck motors but I would like to use the V8 harness but I have heard that you can use the 4.3 pcm but alot of people get the alternator light on the guages is this true and how do you fix it? And also I would like to use the 24x LS2 or LS6 and maybe get a junk 4.8 for the accessories and other parts is there any other complications that I might encounter, also it is a 2001 truck and has cable TB has anyone added cruise control to these trucks?

[Frenchy]

You have the older truck so it's an easier swap. I've heard the battery warning light can be tuned out. Truck or car motor doesn't matter, hell you'll probably get better mileage with a 5.3 than a 5.7 but there is so many variables there I won't get into that. As far as adding cruise I don't know of anyone that's done it, like everything though it can be done.

[texasranger96]

yeah it was my uncle's truck he is getting crippled so he bought a 2010 silverado with the 6spd 5.3 regular cab he loves it he said I should put that motor in it but I think that would be way to involved!

[gottaswapup]

My '06 Sierra 1500 long bed 2wd averages 20+ mpg in mostly city use. I've seen 26 mpg on the open highway. The 5.3 might do similar with proper gearing, but it might be cheaper and easier to just supercharge the Vortec V6. Vortech and ATI are the most likely manufacturers.

[texasranger96]

No if I went that route I would turbo it I think it would be one of the most fuel effiecient trucks ever, is your 1500 stock or modified?

[Crazy Blu]

im not even tuned anymore and getting 430+ a tank... u must drive like a mad man!!!

when i was tuned i once had a tank last to 500+ but i dont speed on the streets at all and really pussy foot it...

[gottaswapup]

No if I went that route I would turbo it I think it would be one of the most fuel effiecient trucks ever, is your 1500 stock or modified?

That 26 was very recent, with a 4L60E, 3.73:1 in 8.625" 10-bolt, 245/70R17, and a tonneau cover, but the engine pure stock. Most of the performance mods are pointless in this thin air up here at 4500' elevation. And no, that doesn't really help MPG, I've taken this truck down the Pacific Coast Highway, and saw the same MPG on that trip as I get around here. I just write the odometer reading on the receipt every time I fill up, then at home get a calculator and divide miles by gallons.
Turbocharging is appealing, but with the weird injection on these, I doubt you could get enough fuel. If there was a way to upgrade these injectors, then I'd love to do a turbo. do it after-cat like Squires STS, and it could be cheaper than a blower kit. Plus more mid-range torque. The downside of boost rather than V89 is with stock pistons, you can't stay in boost all the way up over a mountain, especially not loaded, and why drive a truck over a mountain if the bed isn't full?