This Is an example from my truck. I highlited it with a marking crayon.
It's not very legible but gives an idea of wht your looking for.
A part number will not tell you when it was made and may span many years

 

Looking at the pics he posted on page 2... the date casting is B 23 9

February 23rd 1999

Looks like someone swapped the fuel rail or intake (returnless type)

 

It's not uncommon for a Junkyard to do this. The intakes often get damaged wether from a wreck or from a careless yard monkey.

 

Good Eyes RedXray - Give that man a BEER!!!!!!!!!!!!!!

Yep the date code is B239!

ok Great so I have the returnless rail on my intake, 1 less issue to deal with and I should be good to go on that front. So all I need now is just the harness and I can get this party started. Someone PM'd me last night about an 03 Harness so that might also be taken care of. Unfortunately, I will be too busy this weekend and the following so I will not be able to lay hands on it until the 1st wknd in May.

I will keep you guys posted.

 

Good News Everyone following my post. I bought a complete 03+ Harness from a member here yesterday. hopefully he'll send out within the next couple of days. Fingers-Crossed that this will be the major road block on this conversion and its smooth sailing from here on to Start-up. just for ***** and giggles I have been comparing the 99-02 to 03-07 pin layout, not just for my sanity but so that I can be a lil smarter on the whole wiring schematics deal in case something else happens I can be somewhat prepared.

 

You didn't say if it's a van harness (DBC) or a 03+ drive by wire harness.

One more thing is the oil pressure sensor is also different between 99-02 and 03+. The 03+ oil sending unit is a three pin connector whereas the 99-02 has a single pin... I have the 03+ but need the 99-02 and you'll need the 03+ oil sending unit, dam thing (99-02) is $38 new

03+ three pin on my LQ9

 

Hey RedXray - Thanks for continuing to keep me posted on the differences of this swap. I wonder if the 4.3 Oil Pressure Sensor will swap out?? gonna have to check on that. Ohhh and the Harness is an 03+ "truck" harness that has been converted for DBC. It should be here today - hopefully I'll get some time sooner than later to remove old harness and install the new one.

ohh and I also cleaned up the engine some, yesterday I received the cover. removed all the EGR "CRAP" looks much MUCH better without it. I am getting closer and closer.

 

You got lucky finding the harness already set up for DBC. I also wondered if the oil sending unit from the 4.3 will work but RockAuto shows two different part numbers. Check your new harness to see if the oil connector has three pins or one. Since someone did harness work they may have already addressed that oil connector.

 

Update: I went on the Hot Rod Power Tour last week so the truck has been sitting waiting. Well yesterday I had some time after work so I was able to remove the old harness and installed the newer harness, I started plugging some of the plugs, injectors, Fuseblock in but I ran out of daylight so I will be out there tonight to give it some more time. I'm hoping to have 1st startup sometime before this weekend is over.

wish me luck.

 

Well guys (I know Xray warned me about this) but the Oil Pressure Sensor was the wrong one - I found out the hard way that I need the 3 Pin - so I have a new one on order. Now onto my current dilemma I have a few harnesses that I cannot for the life of me figure out what they plug into.

Now as a reminder the engine is an 99 LM7 and I had to use a Wiring harness from an 03+ Van (in order to keep it DBC) so I am thinking these are probably Van extra accessories harness that I don't have to worry about plugging in. Any help would be greatly appreciated. Also my other issues is that the O2 Sensor and O2 Harness are both Female Plugs - how are you guys fixing that issue? I have pics below - Thanks in advance for the help. I am hoping to have it fired up before the end of the weekend.



Harness plug back near the transmission - I don't know what it is or where it goes. HELP!



Harness plug near the Fuse block in the Engine compartment - I don't know what it is or where it goes. HELP.



How are you guys addressing the Female to Female O2 Sensor issue? I only plan on running the front O2 Sensors if that makes a difference.