I am moving into a new house on the second of march, and after that dust settles I am going to be picking up a third gen, and looking for a donor ls1 f-body.

I am planning on stripping the whole third gen down to nothing, painting the under carriage, engine bay, and every other component. I want the car to look brand new and factory-ish when done. I also want to swap as much of the 4th gen over as I can, I plan on doing the dash swap as well as custom 4th gen seats and the whole nine yards.

I have been researching this for months and have gained a ton of knowledge but still have a few questions I was not able to get definitive answers on.

1st, is the donor car method the best? I was hoping to get a nice rear ended 4th gen for under 4 grand. I know you can pull truck motors for a lot less than ls1 cars, and they perform the same, but I was planning on using the 4th gen cars transmission, rear end, interior, wiring harness, pedals, clutch master, all of that. I think getting a donor car, and selling everything I do not use off the car and scrapping the car ( or even swapping the third gen rear ect over and making it a roller to keep around for a drag car project if its not wrecked too bad ) would be the best bet. But I have never done this before so please enlighten me. What other parts would I need to purchase save for motor and tranny mounts if I had both cars at my disposal?

2nd, would it make it harder or easier depending on the third gen cars original options? Would it matter if I picked up a 6cyl auto or should I look for a v8 car with a five speed?

3rd, and final until I actually have the cars in hand, would be a compound wiring question. Now I am very confident in my soldering/heat shrinking/ and wire organizational skills, but I haven't done much automotive wiring. What is keeping me from just using the ls1 cars harness as is? Why do I have to modify it? Is it simply to remove things that the third gen will not have? I am not going for a race car here and want to maintain all that I can for creature comforts, like A/C.

I know the dash swaps are a pain, but it seems that all the pain comes from getting the stock cluster to work. I do not want to use the stock cluster. I remember when I had my trans am I frequented the appearance and detailing section years back and someone was making gauge template that fit in the stock dash and let you mount a few smaller gauges as well as a tach and speedo ( auto-meter or the like ). I want to make that, and that being said won't the dash swap mostly consist of hvac work, mounting the dash, and wiring up the after market gauges per manufactures instructions? Simplifying the whole process?

Lastly what about using the whole 4th gens body harness? The cars are similar enough that running the wires back there wouldn't be an issue, and I'm sure a few connectors are different as far as tail lamp lights ect, but that can all be changed, wouldn't using the 4th gen engine and body harness make the whole swap ( including the stock cluster if one chose ) basically plug and play save for switching a few light bulb sockets and that sort of thing?

 

Wow...that sounds like a huge project your planning. I've just done a relatively basic LS1/3rd gen swap, and at first I was wanting to go for a full 4th gen dash but decided against it. I've kinda grown to like the dated 3rd Gen design, plus it turns out finding a wrecked LS1 4th gen with any sort of non-ragged out interior/body isn't as easy as I thought it would be.

As for the total wiring swap, there's been a few people on TGO who have attempted it, so maybe a search there would be helpful.

There's a lot of 4th gen parts I wouldn't even bother with, such as the pedals, clutch master, rearend, etc. But the front brake conversion is worthwhile, and of course the LS1/T56 dropout is a fantastic swap, I know I couldn't be happier with mine.

 

Yes this is going to be a huge project, I plan on working diligently and having it done in around 6 months. Its going to cost a lot more than normal because I am going to have to buy all new tools * besides basic hand tools * Engine hoist, air compressor, paint guns ect, as I no long have access to them. I am also going to be painting the whole car myself, SOM. Dismantling the whole car, re fenders doors hatch ect, and jamming everything out the proper way. I hope to find a hard top third gen. I see you say do not bother with the ls1 pedal assembly, but from what I've seen it is hard finding a five speed third gen car, so I'd be short a pedal lol. Should I locate a third gen pedal assembly if my project car is an auto? Isn't the rear end a bolt on deal? I was just planning on using that if I ended up with a third gen with an open diff. I wasn't planning on being very picky on the third gen I get, as I was going to replace everything, just something with no rust. I was hoping to avoid having to be picky here, as I can grab cheap third gens for well under a grand.

As far as the dash I see what you are saying, as long as the dash is in 1 peice it will atleast give me a template to go on, get it mounted then hunt for a nice one. I am going to be replacing the carpet with new jet black carpet, and using professional plastic dyes to dye the dash, door panels, and everything else with black as black can be. I want to try to do everything myself, including re upholstering 4th gen seats with nice leather. I have dabbled in just about every aspect of automotive repair or modification, now I want to really hone my skills and build something.

The over all plan was to get the car on the road, looking amazing, and running even better, but bone stock. Then slowly working on building a rear end, and 6.0L once I can drive the car. This car will see DD duty once on the road. I will still keep my Caddy for the winters, but I miss DD a f-body