Aftermarket harness or bail on this motor?

[chevy72blu]

Hey folks,

I traded a local guy my unfired, relatively built 454 BBC/decent TH350 for an LS1/4l60E combo (98 T/A, 60k miles). It also came with some mounts, nice coated headers, and the PCM. I would say my motor was worth between $3500-$4000, but as many of us know they arent always easy to sell. The problem? No harness! The guy said he had it but it didnt turn up...

Many of my parts have already arrived (Boyd's EFI tank, CPP mounts, etc) and the LS1 I have seems to be in great shape. However, I feel like I lost $$ on the trade and now I will be set back again with a new harness. People keep talking about complete 5.3's being found for less than 1k, but I havent been that lucky in my search.

It looks like most places charge around $300-400 to rework a factory harness (which I would have had to pay). A new, completely stand alone harness can be had from PSI for $500, so I guess its not so bad after all. Everything is just adding up in a hurry. I still havent addressed cooling, driveshaft, plumbing, or speedo yet.

I just wanted to get some feedback on the standalone/aftermarket harness (any issues they present) and which direction you think I should go. I want the truck to be right but I'm not made of money either.

[ls1nova71]

Did you get the PCM? If not, since you don't have a harness, I would get an aftermarket harness and a PCM (12200411) from a 99-02 f body and call it a day. 98's are kind of the stepchild of LS engines.
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[Clyde65]

What he said^^^^^^

[19seventeeCustom]

sounds like you didn't get hosed on the trade though. (even with buying a harness)

I would swap out the PCM with a 99+ fbody unit also, 98s seem to only
bring issues.
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[6.0 1955]

My local tuner won't even tune a 98 computer setup. Switch to 99 up stuff and enjoy. To me having the driveability and fuel savings is well worth trading that BBC for the LS1 setup. Once you get it up and running you will be happy.
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[mcmlxix]

Did you talk to Robbie at MoTech? He's going to build me a harness from scratch. He quoted me around $800 for the harness and tune the ECM. I like the idea that I have someone local to go to if I have issues. He will probably get to building the harness next week and will have an exact cost before then.

My original ideas was www.howellefi.com .... it was about the same cost with an exchange ECM and new harness.

[chevy72blu]

Thanks for the replies everyone.

So I take it a 99-02 harness can be ran just fine on my '98 motor without any modifications? This is the first I have heard about the issues with the 98's.If the 98 harness is a PITA to work with then I suppose I am not out anything to begin with. Makes me feel a bit better at least


I do have the PCM, but I assume it is difference from the 99-02 versions? I could sell it to re-coup some cost.

Yeah, I spoke with Robbie but he quoted me a higher number to do my modify my harness and PCM (higher than Speartech). I havent been able to get a hold of anyone at PSI, but I'll try Robbie again hopefully today.

[ls1nova71]

99-02 harness will work with your 98 motor. The only thing that is different is thr 98's have a 3 wire temp sender where as the 99- up have a 2 wire sender.
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[C10_ustacould]

I am having a similar issue with my 5.3L swap... My engine is installed, I have headers, radiator and fans, fuel system, but I don't like the harness that came with my engine. I looked into a current performance stand alone harness ($725 with A/C and fan relays) and the cost didn't surprise me much because they are really nice, but the wait did! 9 to 10 weeks! I ended up buying their relay/fuse center ($125), I think that will fix the issues I have with mine but I wish I could have gotten their complete harness...

[farmtrucks]

I've bought several harnesses from PSI -- and am very pleased with his work and customer service -- very clean appearance and easy to install. You can also get a flashed computer at a smokin deal.

[kamikazekyle05]

Originally Posted by BucksSS

I ended up buying their relay/fuse center ($125)

This is what im using on my swap with my stock modified harness. I haven't finished up yet but its made wiring soo easy.

[C10_ustacould]

Originally Posted by kamikazekyle05

This is what im using on my swap with my stock modified harness. I haven't finished up yet but its made wiring soo easy.

Mine should be here tomorrow, I am excited to see how it wires up!

[C10_ustacould]

I broke down and ordered a PSI harness this morning. I think it will simplify my installation. I will post my thoughts after the install, with some pictures.
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[Larry Lindley]

I know tkis a little late but I have a 5.3 got emc from spare EMC on ebay,my stand alone harness from Texas Fule Injection.Very good people to deal with.