Seeking Suggestions on my 454 Swap

[lamogo33]

Trying to swap a 94 454 into a 92 chassis that had a 5.7l...

I purchased a 94 454 TB which should be arriving today. In preparation I wanted to swap out the computer and wiring harness and hit a bit of a snag. I noticed that a few connections are not the same between the two, speaking of connectors on the chassis, not the engine. Not sure how to remedy this.

On the 94 harness it has two relays while my 92 chassis only has one on the firewall...

On one of the plugs behind the glovebox, not to the computer, my 94 harness has two 10 gauge red wires in it, and a gray one...

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while the truck only has one red wire, and a green and purple...

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Also, my 94 harness has this plug...

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while my truck seems to have this style...

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What is the best way to remedy this?
Adapt the new TB to my 5.7 harness and buy a chip. I'm afraid this might pigeon hole me into keeping the 700R4 when I do hope to upgrade to a 4L80e later.

Can these plugs be repinned with a tool to work? How time consuming would that be?

Should cut both my wiring harness apart and create a high bred? I'd rather not try this.

Or should I just find a used 4bbl manifold and carb and go that route. hahaha

 

[tanman_2006]

The 454 harness should hook right up to a 4l80

 

[lamogo33]

No suggestions huh

 

[88GMCtruck]

I swapped my 88 350 to a 454, I converted the harness from my truck to the new motor, mostly it was moving some plug locations.

 

[Supercharged111]

I swapped my 88 350 to a 454, I converted the harness from my truck to the new motor, mostly it was moving some plug locations.

This was going to be my suggestion as well. 4L60 harness can easily adapt to a 4L80 too.

 

[lamogo33]

I swapped my 88 350 to a 454, I converted the harness from my truck to the new motor, mostly it was moving some plug locations.

Thanks for the reply.

I've got it to run on my 350 wiring harness with the 350 TBI, using the 350 chip. However, the chip for the 94 does not appear to fit into my 92 computer. So I'd like to use the 94 computer and chip since I have it. Otherwise I think I'll have to buy a PROM for a 92 454 and locate another throttle body for that year. Which is more money than I can spend ATM.

I'm still considering repinning the 94 harness but not sure what that entails. Perhaps wiring diagrams for both trucks?

 

[lamogo33]

This was going to be my suggestion as well. 4L60 harness can easily adapt to a 4L80 too.

Thanks for that! Too bad my 92 came with the 700R4...

 

[lamogo33]

I believe I found a possible solution. It appears I can repin my 92 harness to work with the 94 computer. That is what I'm going to try to do. Thanks.

 

[88GMCtruck]

Thanks for the reply.

I've got it to run on my 350 wiring harness with the 350 TBI, using the 350 chip. However, the chip for the 94 does not appear to fit into my 92 computer. So I'd like to use the 94 computer and chip since I have it. Otherwise I think I'll have to buy a PROM for a 92 454 and locate another throttle body for that year. Which is more money than I can spend ATM.

I'm still considering repinning the 94 harness but not sure what that entails. Perhaps wiring diagrams for both trucks?

Yeah GM changed the computers sometime between, i think in 93 with the advent of the 4L60 electronics.

The 454TBI has different connectors no matter what year, compared to the 350TBI, so either way you will be modifying the wiring to work.

too bad you weren't a few months later, i'm pulling all my harness, chip etc and swapping to vortec.

 

[Chewy1576]

I repinned the ECM connectors from my 1990 ECM (1228747) for a 1994 ECM (16197427). With the right diagram and the new connectors, it was a piece of cake. Here is where I got the info for mine - http://www.gearhead-efi.com/Fuel-In...ersion-PCM-Swap-with-Wiring-Pinout-Directions!

There are some small harness adapters out there for the IAC and TPS to make the 350 TBI wiring plug-and-play with a 454 TB.