New From NW GA With a 1990 K5

Hello Everybody,

Just registered today and have already learned quite a bit. As the title indicates I have a 1990 K5 that I am seriously considering swapping a 6.0/4L80E into. I am fairly mechanical, so that part of a swap doesn't scare me much. What scares the crap out of me is that pile of wires, so if there is anyone here who knows their way around the somewhat basterdized wiring in a 1990 TBI square body blazer, I'm all ears.

If anybody can share any "how to" information on what to take out, and what to wire where into the factory fuse box and how to get power to everything, I would really appreciate it. Also, I have already deleted the factory A/C, so if anybody has any tips on how to delete the A/C from the 6.0 and what belts/tensioners you have to put back in its place, I've got a pen and paper ready.

Thank you all in advance for your help. I know I will learn a lot from what is obviously a very knowledgeable group of people. I just hope that sooner than later I can also contribute and hopefully help somebody out too.

ALM

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Originally Posted by 1990K5

Hello Everybody,

Just registered today and have already learned quite a bit. As the title indicates I have a 1990 K5 that I am seriously considering swapping a 6.0/4L80E into. I am fairly mechanical, so that part of a swap doesn't scare me much. What scares the crap out of me is that pile of wires, so if there is anyone here who knows their way around the somewhat basterdized wiring in a 1990 TBI square body blazer, I'm all ears.

If anybody can share any "how to" information on what to take out, and what to wire where into the factory fuse box and how to get power to everything, I would really appreciate it. Also, I have already deleted the factory A/C, so if anybody has any tips on how to delete the A/C from the 6.0 and what belts/tensioners you have to put back in its place, I've got a pen and paper ready.

Thank you all in advance for your help. I know I will learn a lot from what is obviously a very knowledgeable group of people. I just hope that sooner than later I can also contribute and hopefully help somebody out too.

ALM

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Greg's (RedHeartBeat) write up sticky should have most of the stuff you need considering most of his swaps have been in early 90s trucks. I don't see why it would be any different as far as the wiring is concerned for the Blazer. One thing you need to think about on the mechanical side is how you're going to mount your 80e up to the K5 t-case. I'm sure its setup for a 700r4 or 4l60e, so the inputs are going to be different. You'll have to change the output on the trans or input on the tcase. Personally, I'd be going for the t-case. Look for the write up from Redheartbeat and it should tell you a lot about the wiring. You'll probably want to go ahead and splurge for a stand alone harness from a reputable source, then add what is needed from there.

Thanks for the heads up Pl4yboy. I will definitely give that sticky a thorough read. You are correct about the current setup. It is a 350/700R4/241C combo. I was under the impression that in the 1990 models, the t-case had a 32 spline input, which I believe is what the 4L80E has, but I haven't looked that far into it. Depending upon how much cash I have in-hand when I get that far, if the 241C has the correct spline count, I may reuse it. If not, and money permits, I may go with the modified TH400 adapter from Advance Adapters and bolt an NP205 up. With that comes extra machining to fit a tone ring for the speedometer (I think. Someone may correct me on that, as the 4L80E may send the speed signal, rather than from the t-case as it currently is with the DRAC/VSS.

As for harnesses, from everything I've been able to read so far, it looks like Nelsons and a few others are the most highly recommended. No reason to argue with that, so I'm sure I'll go that route.

Thanks again for the information.

I'm not sure on the t-case spline count, so I can't help there. Just thought I'd throw it out there before you ran into the issue at a critical moment in the swap and stuck without funds or time. I've been there! Nelson and Painless both make great harnesses, but remember, they are simply stand alone to get it running. No gauges or anything else. That's on you.

Spline count isn't the issue, its the size of the output shaft. TransmissionCenter.net makes an output shaft for the 80e that is the same size as a 700r4 output shaft. You have to pull the 80e all the way apart to replace it but you don't need any special tools to take one apart other than a pump puller.

As far as removing the AC from the 6.0, it couldn't be any easier. The AC pump is mounted on its own bracket and has a dedicated belt. Simply remove the belt, pump and bracket and you are good to go.

Welcome!

Welcome and post up some pics.

Thanks to everyone for all of the input so far. I will try to figure out the pics thing and see what I can come up with. I'm a total idiot when it comes to computers, so we'll see what we get :)