Seeking Information on a 454 Swap

[lamogo33]

I recently came upon a well cared for 92 k1500 ECSB with what I expected to be a bad engine. I drove it three blocks home and have been contemplating of what to do with it since. I wish to use this truck as a tow rig (dragging cars home from time to time) and thus it needs to replace my BBF dually. I have located a SBC out of another TBI truck with 180,000 on the odometer, but I hate towing with a small block. So I have a few options.

I have located a 96 454 4x4 Surburban (Vortec) I might buy but I'm thinking there would be too much to change over. ie brackets, computers, hoses, etc.

I have also located a 454 with 4L80E already pulled from a 94 GMT400. This would include computers, throttle body, pulley brackets, etc... it even includes the exhaust system.

I believe the latter engine would be a near direct bolt up, but I am looking for any information on anything that might be out of the ordinary for this swap. Will the headers work for a 1/2 ton chassis? I know that some complain about HP/TQ ratings of the TBI BBC but they are comparable to my 460 so I wont mind. I live in a very isolated community and the nearest wrecking yard is 100 miles away so odd and ends will become a problem if I have to source them. BTW the 4L80E is a 2wd so I might just use the 700R4 for the time being, since the TBI doesn't have too much power, and know not to tow in OD.

Any help on what this might entail would be helpful, thanks.

 

[Champ]

I don't know about swapping the 7.4 Vortec in and what changes that would entail, but I have swapped a 454 TBI from a 95 K2500 into my 93 C1500. However, I converted it to a carbed setup.

You will need to extend the three wires that run to the oil pressure sender/fuel relay switch, because the sender is on the back of the intake on the 350, and is on the front passenger side of the block on the 454. All the other wiring should be plug and play except for the plug for the TPS. I'm not 100% sure but it may be a different plug.

To run a 454 in the 1/2 frame, I used a set of Hooker headers for a 454SS truck. I originally tried to use headers for a 3/4 ton 454 truck, but they didn't seem to fit. I'm not sure that the headers I used would work in a 4X4 truck due to the transfer case. Mine exit about six inches from the transmission crossmember.

I'm also not entirely sure about the wiring for swapping to a 4L80E from the 700R4. The R4 will work behind the 454, but it may not be ideal. You don't have to swap the entire computer to run the 454, just the PROM.

I wish I could be of more help, but hopefully that'll get ya started!

 

[lamogo33]

Thanks for the reply. Sounds as straight forward as I had originally thought. I found a set of Hooker headers that say they fit all C/K series trucks and 454 engine #2461. Thankfully, the seller of the engine kept the wiring harness from the donor truck so that should be a non-issue with this swap.

And I agree that the transmission is not ideal. I may swap in the 4L80E once winter is over and I do not need a 4wd rig as imminently.

 

[Christian Steffen]

If you can get everything (whole truck) to swap to the vortec 7.4, you'll be much happier with that over the tbi in my opinion.

 

[lamogo33]

Yeah, I'd be buying the whole truck if I went that route. However, I am not sure of the trucks condition. It might be too nice to rob an engine out of... Plus it is buried in snow a mile off the highway on a dirt road. Might not get to it till spring.

 

[Christian Steffen]

I'm sure it'd be more enjoyable to work on in the spring. Hopefully the truck isn't too run down, it'd save a lot of work if everything is usable.

 

[lamogo33]

You will need to extend the three wires that run to the oil pressure sender/fuel relay switch, because the sender is on the back of the intake on the 350, and is on the front passenger side of the block on the 454. All the other wiring should be plug and play except for the plug for the TPS. I'm not 100% sure but it may be a different plug.

To run a 454 in the 1/2 frame, I used a set of Hooker headers for a 454SS truck. I originally tried to use headers for a 3/4 ton 454 truck, but they didn't seem to fit. I'm not sure that the headers I used would work in a 4X4 truck due to the transfer case. Mine exit about six inches from the transmission crossmember.

You mention this pressure switch is on the passenger side. Are you certain? I found a broken switch on drivers side up near the front of the block. Is that it? Mine is broken and I'm going to replace it, just want to make sure we are on the same page. Thanks!