Official NBS 4.3v6 to GEN 3 V8 swap Guide

[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?

[Frenchy]

Well first off, congrats on getting it going

[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...

[Fadingglories]

I got my harness all squared away. A the owner from KNOX Auto Supply was a real help and was able to next day air ship me one from TN so i could still do my swap this weekend. Hey also when doing this v8 swap can you use the stock v6 torque converter???

[zebra]

Well first off, congrats on getting it going

thanks

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...

yep - cable throttle (DBW started in 03). tomorrow, i plan on getting some MAF cleaner & spraying the IAC down & also resetting the TPS (i was told to disconnect the negative battery for 10min while i remove & reinstall the sensor)

as for the cold... well, it ain't really. even if it was, i would understand it idling high (around 1500-ish) for a minute, but living around 500 or less is wrong

I got my harness all squared away. A the owner from KNOX Auto Supply was a real help and was able to next day air ship me one from TN so i could still do my swap this weekend. Hey also when doing this v8 swap can you use the stock v6 torque converter???

Knox Auto was a let-down for me. the shop owner where i did my swap gets stuff from them all the time & i bought an 02 L59 from them but when it got here, the harness was cut & some of the accessories i bought were missing
the replacement 02 LM7 they sent looked like crap (from sitting on the warehouse shelf for 3 years [keep in mind, i specifically said to not send an engine that'd been sitting more than a couple months]) and was missing an exhaust manifold. we just ended up doing a complete return/refund.

a month later, i finally found a fresh (in the yard a month, still in the truck) 01 LM7 in tompkinsville, ky

as for the V6 converter - i believe you can use it, but i'm a standard guy so what do i know?!

[banker099]

Hey also when doing this v8 swap can you use the stock v6 torque converter???

yep...i ran mine for about a year, till i got a cam/stall

[DennisG_02Silverado]

yep...i ran mine for about a year, till i got a cam/stall

how long has your transmission lasted?

mine just went out saturday after doing full exhaust thursday. so now i gotta wait ti get some more money to get tranny built

[DennisG_02Silverado]

here's some pics of motor and swap completion:

[banker099]

how long has your transmission lasted?

mine just went out saturday after doing full exhaust thursday. so now i gotta wait ti get some more money to get tranny built

well this Dec will be 2 yrs since my swap....still going strong....my truck/trans has bout 75000 on it, so take that into consideration, has a no TM and just a corvette servo, and trans cooler