Official NBS 4.3v6 to GEN 3 V8 swap Guide

[Fadingglories]

is this difficult to do? what parts does it require?

[banker099]

nelson sells a harness that make it super simple

[Fadingglories]

I hit a block in my conversion because i found out i have a 06 wiring harness and it obviously won't work on my 99 and wiring harness' don't grow on trees. Here are a couple of pictures of my swap progress.

[DennisG_02Silverado]

nice... i pulled my harness off a a Cash For Clunkers Truck

[Fadingglories]

Yeah thats what i'll probably end up doing. Do you know how much your junkyard charged you? I imagine even from a junkyard it was a pretty penny

[DennisG_02Silverado]

paid 100 for mine. most of them i wanted between 125-150

[cjcalhoun]

if u want to sell that harness let me know

[zebra]

so mine's running as of last thursday - the no-spark was a computer issue, got the tune fixed & it fired right up. HOLY CRAP!!! the 5.3 (even as stock as it is) is so much better than the v6! i really have a hard time keeping my foot out of 2nd gear.

some quick questions, though...

what would cause the message center to keep flashing the red battery picture? it'll be on a few seconds then off a few seconds over & over. i have a new battery & the alternator tested fine.

also, the idle is acting a little funky. when i start it, it jumps to about 1900 then settles to about 700-800 (tune is set to 700). after a little bit, though, it'll slowly drop to around 500 & occasionally dip to 475-450-ish when it's in neutral or with the clutch in.

another thing is do the V6 & V8 use the same VSS? or is the tachometer calibration different? the reason i ask is because the speedometer seems to sometimes be mathematically off a bit from the tach - for example: around town, it seems to be fine, but on the interstate, i was showing 2000rpm and 61-62mph. with my 265/75-16 tires, 3.73 gears, and .73 OD i should be doing 69mph at 2000rpm. i'll have to check to see if the odometer is accurate next time i go to work. i called the tuner & he looked up my tune & said the tire size & diff gears were set correctly. any ideas?

[Fadingglories]

"also, the idle is acting a little funky. when i start it, it jumps to about 1900 then settles to about 700-800 (tune is set to 700). after a little bit, though, it'll slowly drop to around 500 & occasionally dip to 475-450-ish when it's in neutral or with the clutch in."

By your year i'm assuming you have a throttle cable style intake and not fly by wire. I am not sure but it may be your throttle positioning sensor or motor. These two items are located on the drivers side of the throttle body and could contribute to your wierd idle because in the winter when its cold my v6 does the same thing and my mechanic told me it was one of these culprits. As far as your guages and tach not working i don't have a guess on that one...

[Frenchy]

Well first off, congrats on getting it going