5.3L (LM7) into OBS Silverado

[1BADC10]

Does anyone (or allen) do harness graftin'? I'm in need of ideas for graftin' a 5.3 engine harness into the OBS ('86) fuse block (engine compartment). I'm not sure if it's best to graft the engine harness straight to the OBS fuse block, or use the fuse block I have from the NBS truck (engine harness to NBS fuse block to NBS gauge harness to OBS fuse block).

HELP!!!

[farmtruc]

Are you going to use the stock cluster? Are the gauges electronic or mechanical?
I'm sure most of the gauges in the truck work independently from the computer.
What where you wanting to graff together?
The engine harness I supply kind of runs on its own. Hook up a few wires and you're done. If you have a few spare fuses on the stock fuse block, you could easily remove the one I supply and run it through the stock one.
The other wires on my harness are batter and ground. You could run the batter wire through the stock fuse block too.
The ground just bolts onto the cylinder head.

For the water temp gauge, simply use the three wire temp sensor. The fuel gauge should be stand alone. The oil pressure can be reused on the new engine. The volt meter/ampmeter usually works without hooking anything up to the pcm.

Hope this helps, let us know if you have any more questions,


allen

[1BADC10]

I'm pretty sure I can graff the NBS engine harness directly into the OBS fuse block. Someone has already done this in Tennessee (Dana Dash did it for a guy who works for Tennessee Auto). I'm planning on using Dakota Digital 73 - 87 cluster kit (electric gauges). They'll have the speedo, tach, oil press, water temp, volts, and fuel gauges.

Questions:

#1 - Is there a need to have the '02 fuse block, or should I just graff the engine harness directly to the '86 fuse block?
#2 - What would it take to make wiring provisions for e-fans?
#3 - If above is possible, how much are your harnesses?

***edit: #3's answer is $550, right? Saw in another post.

[TXcrew]

ALLEN IS YODA..

[farmtruc]

Originally posted by zro26t@Dec 31 2005, 07:03 AM
I'm pretty sure I can graff the NBS engine harness directly into the OBS fuse block. Someone has already done this in Tennessee (Dana Dash did it for a guy who works for Tennessee Auto). I'm planning on using Dakota Digital 73 - 87 cluster kit (electric gauges). They'll have the speedo, tach, oil press, water temp, volts, and fuel gauges.

Questions:

#1 - Is there a need to have the '02 fuse block, or should I just graff the engine harness directly to the '86 fuse block?
#2 - What would it take to make wiring provisions for e-fans?
#3 - If above is possible, how much are your harnesses?

***edit: #3's answer is $550, right? Saw in another post.

IF you're using all electronic gauges, then you'll simply be able to tap into the new LS1 Harness.
I do supply a wire for tach and speedometer, so that's two down. Use the three wire temp for the water gauge. The fuel and volt meter will probably already work.
Sounds like you got it down.
The fuse block I supply isn't needed if you're using the original fuse block. Just find a couple of extra ignition spots, battery and ground it, you're done.
I'd say use the orginal fuse block, you'll probably have extra spots open after you remove the original engine harness.
If you don't want to do that, the fuse block I use is only a 4 bang fuse block, so it's very small and can be hidden or installed anywhere.
Fans: we're actually going to offer that as part of the harness too.
We'd simply add our current harness into the engin harness.
I'll need to know what kind of fans you'll be using and will you be using A/C.

thanks guys,

allen

[1BADC10]

OK, when you say original fuse block, are you referring to the '02 or my '86? Yes, I'm planning on running A/C. How much for the e-fan harness. I'm goin j/y shopping on Monday. I found some goodies that I'll need.

Is it necessary to use the '02 fuse block with all the relays & such? I'd like to just have the engine harness directly to my '86 fuse block.

BTW... this is what went in this morning... Took some doing (V6 to V8 brackets, slotting the mount holes on the brackets, and a nice trusty hammer):

[RedHeartbeat]

Use the factory starter lead. Hook the old engine coil lead to the wire harness power feed. If it has a voltage drop resistor or fusible link it will need to be removed. Connect the old alternator light lead to the small lead coming out of the alternator. Run the old alternator lead to the new alternator. Does your truck have an electronic oil pressure guage? I had an old 1998 broken O/P unit so I tapped it to fit the OBS sensor and installed it in the factory location since my 2002 F-body PCM doesn't care if I have O/P or not. You also can tap the little fixture bolted on the oil pan next to the oil filter. For water temp readings use the three lead water temp sensor from the 1998 F-body. One word of caution when filling the radiator with water, leave the air bleed line off on the engine while filling until you start to get a steady stream of water running from it. If you fail to do this you may end up over-heating.

[farmtruc]

The original fuse block is the 86 fuse block.

I thought this was a neat idea.

Do you notice the outlet on the waterpump is on top for the truck and going out the front on the camaros. Well I saw a swap that used the LS1 engine and the LS1 waterpump. So, the outlet was coming out the front. Now you see that air bleed outlet on the top corner front of the head that usually goes through the throttle body, then to the top of the radiator. That line was ran differently. The top of the waterpump, where the truck outlet usually goes, was tapped with a 1/8" fitting and the air bleed tube on the head went to the top of the waterpump, which is a lot easier than trying to run it to the radiator if you're doing an obs swap and don't have the nipple on the radiator for the hose.
I have the truck waterpump and I'm going to tap the front of the water pump, where the camaro waterpump outlet is, then run my airbleed to this fitting. I'll just need a small 1/8 90deg brass fitting to make sure it points up to the air bleed.

The swap looks great!! Get ready to haul ass!!

allen

[Tim Z]

that motor looks right at home there, good work!

[RedHeartbeat]

Hey, Allen. Where did you see an engine with the water pump tapped on the top where the truck radiator outlet is? That was how I did my 92 LS1. Being that I put 2002 heads on my 98 you'd never know it was a 98 unless someone checked the serial code or saw where I JB welded a piece of the block on the driver's side. I had water in a bolt hole when I put the heads on and when I torqued the bolt on the bottom front bolt on cylinder 2 it blew out a piece of engine block.

On my 93 LS1 conversion I tapped a hole down by the heater hose outlets instead.