modifying 4.8 vortec wire harness need help.......
 

Dropping the motor in my 67 already, got told I need to modify thee wire harness but clueless on wat to do anyone have a diagram or can tell me exactly wat to do...

Re: modifying 4.8 vortec wire harness need help.......
 

Go check out LS1tech website, I understand you can get everything you need there. There is also a good writeup in the FAQ that mentions the wiring stuff. It might be called a 5.3 swap on the cheap or something.

Goodluck.

Re: modifying 4.8 vortec wire harness need help.......
 

I went to lt1swap.com and got the pinouts for my harness, ive printed them out and went down each pin to see if i needed it or not

Re: modifying 4.8 vortec wire harness need help.......
 

wait 4 me performance will hack up your harness and tune with free unlimited retunes for $360. i sent mine off yesterday. they eliminate the vats, not just some added box like most.

Re: modifying 4.8 vortec wire harness need help.......
 

cool thanks hopefully i get it done pretty quick i want the truck running already... what do yall plan on doing about the gauges, can we use the new a/c system?

Re: modifying 4.8 vortec wire harness need help.......
 

Here you go

http://www.ls1tech.com/forums/conver...shortstep.html

http://67-72chevytrucks.com/vboard/s...d.php?t=244448

Re: modifying 4.8 vortec wire harness need help.......
 

gauges, you have to have the comp reprogrammed to sent out a v-8 tach signal, you can drill and tap plate above oil filter to make oil gauge work, rt head near the rear their is a plug you can remove redrill and tap for temp sending unit.
if using a transmission that doesnt have a speedo cable you need an eletronic speedometer (definatly cheapest and easiest fix, but not the only way to do this)
im putting an eletronic speedo behind my factory gauge face and needle. im thinking a 94ish s-10 speedo will "work"

Re: modifying 4.8 vortec wire harness need help.......
 

Id like to see and hear more about this

Re: modifying 4.8 vortec wire harness need help.......
 

also most aftermarket tachs have a switch/s to make the tach read 4/6/8 cyl. you can simply put the tach into 4cyl. mode and it'll read accurate, w/out changeing the tach output of the PCM.

Re: modifying 4.8 vortec wire harness need help.......
 

ill be sure to take lots of pics, and if i get it to work ill post up a how to. i think i heard about somebody else on the board doing something simmilar.

Re: modifying 4.8 vortec wire harness need help.......
 

Another option for the oil pressure gauge is to just use the stock hole behind the manifold. The PCM doesn't need the stock sending unit signal. Adapter bungs are also available for the temp sensor if you don't want to drill and tap.

Re: modifying 4.8 vortec wire harness need help.......
 

You have to make an adapter though the LS oil sender seals with a gasket and straight metric thread the "truck" sender will be pipe.

Re: modifying 4.8 vortec wire harness need help.......
 

Although it's an older thread, I'm gonna move it to the LS swap area.