1980 Pontiac Firebird With a 6.6L 400 Engine for Sale in Denton, TX

Last Updated

August 12, 2026

By

Emran Ahmed

If you’re browsing classic Firebirds, this one stands out from the rest right away. The seller states it has a swapped 6.6L 400 engine, runs and drives great, and is asking for $34,990 in Denton, Texas

But it’s far from the pristine example that a buyer may hope to find

The seller makes clear there are dents from hail on the roof and trunk, along with the paint being scratched and pitted. It goes for $35,000 asking price and is open to negotiations, but buyers should be aware that it’s a work in progress.

The engine is the big draw, but condition is the reality.

The 400 Engine is the Reason You’re Here

The 400 cubic inch engine that fires up under the hood wasn’t available in a 1980 model year Firebird.

According to Hagerty’s 1980 Firebird guide, the 1980 model year saw the end of an era for the Firebird. The engines available to choose from included the Buick V6, Pontiac 301 V8, Chevrolet 305 V8 for California models, and the turbocharged 301 V8 for the high-performance. The 4.9-liter turbocharged V8 produces 210 horsepower.

The 400 cubic inch engine is therefore a modification

and can be exactly what a classic car buyer is looking for. A person seeking to find a stock example will likely be underwhelmed by the engine upgrade.

The listing doesn’t specify the engine details of the swapped 400 cubic inch, the year it was manufactured, or the transmission it was fitted with. The engine swap and the mechanicals are an important consideration

that would inform my decision as a buyer.

What Does the Listing Actually Say?

Here’s what we can actually verify based off the listing details:

Item Details

Year 1980

Make Pontiac

Model Firebird

Engine swapped 6.6L / 400 cubic inches

Running condition according to the seller is very good

Asking price is $34,990

Price is negotiable per the listing

Location: Denton, Texas

Roof has hail damage

Trunk also has hail damage

Paint is scratched and pitted

Mileage is not listed

Transmission is not listed

VIN is not listed

Title status is not listed

That’s not a lot of blanks to fill in with guesses

For an older car, mileage, title, and VIN help establish the vehicle’s value. Transmission, and engine details determine the mechanicals.

The Cosmetic Condition Isn’t Pretty

The listing makes it clear that the car isn’t going to win any beauty contests.

Hail damage mars the roof and trunk, and the paint has its share of scratches and pits. The car has a few issues, and a buyer should think long and hard before spending $35,000 on a car with cosmetic damage. On the other hand, the damage could also be seen as an opportunity. A buyer who is looking towards older cars for a project car might be entirely comfortable with the cosmetic condition of this Firebird

I would want to see the roof and trunk in person before finalizing my decision to buy the car. I would want to understand just how bad the hail damage is

A picture can sometimes make a dent look like a small bump. Standing beside the car can give a vastly different impression than looking at the car from a distance over a larger panel.

What to Ask About the Swapped 400

The 400 cubic inch engine is a definite draw, but there are further questions I would ask before discussing price with the seller.

Ask the seller about the engine identification and casting numbers, where the engine was sourced, and whether they have any receipts for the swap. I would want to know about the transmission, who the installation was done by, whether the cooling system was modified, the fuel system, exhaust system, whether the engine has been rebuilt, maintenance records, and receipts for the swap. I would also want to know if the engine runs smoothly and if other car components are functioning properly

The listing doesn’t say how many horsepower the engine has, and I wouldn’t guess at it. The 400 cubic inch engine could have varied specs depending on the engine.

Does it Actually Run and Drive Well?

According to the listing, yes

I would take that as a positive sign, but it’s still the seller’s word for it. If you’re going to be the one spending $35,000 on this car, I would suggest taking your time with the test drive. Read the temperature gauge and listen out for unusual noises. Take note of the car’s braking, steering, suspension, and transmission. If possible, have the car looked at by a mechanic who is familiar with older American vehicles. It’s a worthwhile expense.

What Was a 1980 Firebird Like Back Then?

This is where the swapped engine becomes a draw

The 1980 Firebird has a special place in history. According to Hagerty’s 1980 Firebird guide, the 1980 model year saw a drop in Firebird sales, while the power of the Trans Am peaked at 210 horsepower. The same resource lists 1980 Pontiac Firebird base models with 265 cubic inch V8s producing 120 horsepower each.

The 400 engine in this car is not typical of the powerplants available in a 1980 Firebird.

The engine swap is what makes this car stand out. The enthusiast buyer would be attracted by the modification. And that’s exactly what the seller has done with this car.

Is $34,990 a Lot for This Car? It Depends

It may well be an asking price for this Firebird, but it can come with several caveats.

We simply don’t know enough about the car to say that the price is either good or not good for the moment. We don’t know the trim, mileage, or title. We know even less about the transmission, engine, or overall mechanical condition of the car.

A comparison would be helpful. According to Hagerty Insights, here is the value of a 1980 Pontiac Firebird.

Based on Hagerty’s valuation tool, we can see that a 1980 base model Pontiac Firebird has a value of approximately $8,100 in #3 Good condition, while recent sales of more desirable 1980 Trans Am examples have reached much higher numbers. Hagerty records a $37,018 sale for a 1980 Firebird Trans Am in June 2026. These figures shouldn’t be seen as an absolute price guide for this car. This Firebird has a non-original engine and body damage, and we don’t know its exact trim. That’s why comparing it to just one other Firebird isn’t enough.

Before Making an Offer

I would want to know a few things before making an offer.

First of all, I want to know the VIN. You always want to know what you’re getting into when it comes to a car purchase. Ask the seller about the title, too. The listing says nothing about it being rebuilt or salvaged. Ask the seller about the mileage. It isn’t available in the listing. Ask the seller about the engine. There’s more to it than the casting numbers or 400 badge. Take a look underneath the car. While the listing makes it clear that hail damage on the roof and the trunk is present, it doesn’t say much about rust, frame, or other serious issues. Take a look at the swap. I would be wary of leaks, improper wiring, and rushed fabrication. Get an inspection, especially if you’re thinking of spending nearly $35,000 on a car.

Would I Go Look at It?

If you’re a Firebird enthusiast and you’re local to Denton, I would at least take a look at it. The 400 engine is the kind of swap I would be interested in, and the seller is upfront about the car’s condition. But I wouldn’t take the $34,990 asking price at face value. There were too many missing details for me to do so. A good inspection can open my eyes to a number of things. If the swap was well done, the rest of the chassis was sound, and the title wasn’t damaged, that would be one thing. If the body requires a complete respray and the engine swap lacks paperwork, that’s another. And since the seller has made it clear that the asking price of $34,990 is negotiable, these findings can give you something to actually negotiate with on the price.

Quick Questions Buyers May Have

Is the 400 engine original to the 1980 Firebird?

No. The engine, according to the seller, was swapped in. The 1980 model year Firebirds didn’t have a 400 cubic inch engine at the factory

Does the seller say the car runs?

Yes. It runs and drives very well, according to the listing

What damage does the car have?

The seller says the car has hail damage on the roof and trunk, along with paint being scratched and pitted

How much is the Firebird?

The asking price is $34,990 and is open to negotiations

Where is it located?

Denton, Texas, according to the listing

Is the mileage known?

Not from the supplied listing

Is the transmission known?

No. Transmission information is not available from the original post

Final Word

There’s an obvious reason why this Firebird stands out from the rest. Someone fitted a 6.6L 400 in a car that wasn’t meant to have it at the factory. Whether or not that’s a good thing is entirely up to you

If originality is important to you, the engine swap may be a turn-off. But if you’re looking to find a classic Firebird that has a bigger engine than the factory intended and you can look past the cosmetic damage, this car may be of interest to you. Just don’t let the 400 engine distract you from the rest of the car. Check the title, get the VIN, and ask exactly what engine is fitted. Take a good look at the hail damage. Look underneath the car and get an inspection. It’s those steps, and that information, that will help inform your decision on whether this Firebird is worth the $34,990 asking price.