LT1 Engine Swap

General LT1 Swap Guide


Contrary to what many people are led to believe, the LT1 swap is, in general, not that hard. For the most part, its just like swapping in any other small block Chevy. Modifications must be made for A/C, cooling, power steering, and fuel lines, but nothing so involved that a first-time swapper couldn't handle.

 

The specs of the LT1 used in my swap:

'95 F-body LT1
Auto ECM w/ complete harness
all accessories
30K miles
$1500

 

Tips to simplify an LT1 Swap:

 

1. Have everything you think you will need, on hand, before you even think about touching anything. Even still, there will be parts forgotten.

2. Do not cut any wires until you have at the minimum basic wiring diagrams, or buy an aftermarket harness.

3. For most applications, a TPI fuel pump will be fine.

4. A Fourth-gen radiator is not necessary, but greatly simplifies hose routing.

5. A/C CAN be kept. The crossmember must be notched directly above the passenger side motor mount. You will need an A/C adapter from CarQuest to connect the hoses. The adapter has a 90* bend in the tubing directly off the compressor, keeping the hoses from hitting the crossmember and frame. Another advantage of this nice piece of hardware is that you can turn the fittings any direction need to route the hoses. I still don't think I would have A/C if not for this part. Thanks Gene.

6. Aftermarket or special motor mounts are not necessary. The passenger side uses a modified original mount that has the front corner ground down to clear the A/C compressor. The drivers can use either mount. Both must be moved back from their stock location.

7. Custom fuel lines must be fabricated. The simplest way to do this to reuse the stock hoses that connect to the hard line. Then, use a couple of AN fittings to connect the 4th gen plastic lines to the rubber hose.

8. The wiring harness can be simple, or a nightmare, depending on your confidence, will power, and electrical knowledge. In reality, there are seriously only about 8 wires out of the entire original harness that must be retained, all the rest can be cut out. To know which ones must be cut, however, you will need at the minimum some wiring diagrams from a Chiltons manual or something like that. I was able to get my hands on the diagrams from the GM service manual, and this greatly simplified the harness construction. Also, VATS can be retained. All that must be done is to replace the VATS module with a new one, rewire the connector as per the 4th gen, and splice one wire into the ECM. The hardest part is actually finding and replacing the VATS module itself.

9. Most importantly, if you think you are getting in over your head, stop working and get ahold of someone who has done the swap before. Any of the members listed on the swap registry would be glad to help and answer any question you have.

 


 

As a college student that doesn't have his car with him, I am having to do this swap guide off the top of my head. At a later date, I and most of the swappers from Thirdgen.org will compile our experiences and put together a complete and comprehensive swap guide. For now, I will continue to add to this simple guide as I remember more from my swap and as I see questions come up on the message board. Please feel free to e-mail me if you have any questions. I will always try to answer them quickly and to the best of my ability.

 


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© Tristan Reeves
October, 2002
All rights reserved



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