Hi all!

TLDR: I am looking for advice on the difficulty/time and approximate budget that would be needed to swap a 2.8 into my stock Duke'd 4-speed '84 Fiero, and any advice and experience from those who are/were in a similar situation.

I have done extensive research on the swap and believe I know most of the parts that are needed, but I find it very hard to get an idea of the time and money that would be required for the swap. I'm not entirely sure of whether I want to replace the ol' Duke, as it has been the center of my project after the car sat for 2 decades, bringing it back to life and slowly getting it reliable, but the lack of power is definitely noticeable. Living in CA it seems like the 2.8 would be the most surefire option to get more power keep it legal with the CA BAR requiring all smog equipment to be stock and functioning and having to come from a car with a manual transmission, as it seems a Duke would need a ton of money and at some point would likely have issues passing smog with a cam or even just intake/exhaust.

I love my Fiero as it has been a passion project for a few years now, slowly bringing it back to life and getting it somewhat reliable, but the lack of power has been definitely noticeable. I'm not sure if I would want to keep it long-term as the limits are low and hard to approach with the substantial lack of power, and it seems pouring money and time into suspension and brake restoration and upgrades wouldn't be "worth it" if I can't get up to that speed in the first place, and with lower fun overall from a handling and speed perspective.

At some points a higher powered sports car or Miata have been tempting as they would have great handling characteristics and significantly better power for a lower price point, but the Fiero means a lot to me now as I rescued it in the first place and it has been a huge and (mostly) fun adventure, so if there's a way I can improve my Fiero and still be able to enjoy it with the benefits of more speed and fun on backroads that would be great, and a swap seems to me the best way to do that.

Any feedback from those who were/are in a similar situation would be greatly appreciated, especially in terms of options, whether it would be worth it, or just overall experiences would be great.
Thank you.

[This message has been edited by 842m4SE (edited 10-25-2022).]

Hi,

I am pretty well versed in swaps. I hate to be the bearer of bad news but this is what I was told several years ago, but if you have to ask "how much the swap is going to cost?" and "What do I need for the swap?" you are not ready to do a swap.

Now, hold on I don't want to be a bitter fuddy duddy about it. I will give you my best walkthrough, but I am also going to explain why your question is so hard to answer.


First and foremost, the 2.8 v6, while it makes slightly more power than the L4, you are still going to be wanting, and you will loose any semblance of reliability. The only reason I mention this is because you mentioned reliability in your original question in regards to the L4. The L4 is always going to me a significantly more reliable motor than the V6. The iron dukes are not powerhouses but they are built to always get you home and the mail to your door.

The cost of the the V6 swap is going to vary in eyewatering amounts. It depends on a huge variety of factors. If you manage to find a front impact donor car, it might only cost 500 bucks. If you have to to piecemeal things together it could be 3000 dollars. You will need. The engine, cradle (If you don't want to have mounts fabricated, the v6 and I4 use different mounts), transmission (Must match cradle), associated bellhousing components, (clutch flywheel, pressure plate, fork, TO) Wiring harness, Slave cylinder (depending on transmission), ECM, and a gauge cluster. You will need the decklid and vents from a 85+ car as the 84 decklid and center vent will not clear the V6. You must have wiring experience, if you cant secure a complete harness from a donor car.

Labor will be a moot point if you are doing it yourself, if you are not expect about 40 hours of work (40 x shoprate)

All of this varies depending on how you source your parts.

The biggest problem with swaps though for greenies is that when you cant outright see what you are going to need for a swap (generalized) you might find yourself struggling to make things work, which usually results in the car in a shop and the price rapidly rising as shop hours pile up.

Don't mean to pop your bubble. If you are confident in your abilities ignore me and go for it! We are all here to help you along the way! But my first simple 2000 dollars swap ended up being a 10k debacle, but now I have the experience to do it again for cheap and help others achieve theres!

The hardware will essentially be a bolt-in.
The real issue will be the wiring. The 84 had the C500 connector in the middle of the firewall. Right where the V6 exhaust manifold will need to be. The later cars relocated it to the side of the compartment, in front of the passenger side shock tower. There are also circuits that *just aren't there* in the 84, that the V6 will require.

But... it has been done.
https://gafiero.akroncdnr.com/docs/84v6.pdf

I did this in an 85 base model and it was pretty simple, had to weld a new mount to the cradle, kept my existing 5 speed, exhausts lined up good and only needed a piece of tubing to connect them, wiring plugged right in and I just needed one additional fuse for the second bank of injectors.

Since the 84 never came with a v6 it will be more challenging at least in the wiring department, and possibly miscellaneous things like mounting tabs for the v6 intake and whatnot. I would recommend just going with a 3800NA motor and keeping all emissions stuff, and those came with manuals in camaros and things so shouldn’t be a problem legally. The swaps are more well documented than any other and every part you need is probably available to purchase including plug and play wiring harness and computers and tunes. There’s also a ton of them and they are dirt cheap. They would bolt to your trans and I’m pretty sure you can purchase an engine mount that works with the stock mounting location on your cradle.

I had many reliability issues with my 2.8 (first one had tons of blow-by and second one had lots of wiring issues) and the 3800 will be way more reliable, much more powerful, and you will get much better gas mileage. It has much better gaskets, oiling, and it is super stout and can take a beating. The electronics on the 2.8 are just not good. I got my 2.8, wiring harness, intake, and motor with mount for free. If I had to choose between paying for the parts for a 2.8 swap vs 3800 swap, 3800 hands down.

Just my opinion. 2.8 sounds very good though, that’s its main redeeming quality. Search user 30+mpgs for his 3800NA swap thread.

In terms of the front transmission mount, which set of holes would you use to put a 2.8 on an 84 cradle?

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88 Formula