The third-generation Mazda RX-7 was arguably one of the most beautiful cars ever produced. Its elegantly sleek styling was backed up by a potent twin-turbo rotary engine and superb handling characteristics. The only issue is that rotary engines were never known to be reliable.

How do you make a third-generation RX-7 more reliable? Simple! You conduct a really expensive engine swap like this YouTuber did.

Engine swapping a Mazda RX-7 can cost a pretty penny

Many Mazda RX-7 enthusiasts – or just Mazda enthusiasts in general – would consider swapping anything other than a stock 13B rotary engine into the RX-7 blasphemy, but one YouTuber decided to go against the grain. Ben, from the YouTube channel Gears and Gasoline, recently detailed how much it cost him to build a third-generation Mazda RX-7 with a Honda K20 swap (from an Acura RSX), and the results weren’t pretty.

For starters, Ben said he purchased the Mazda RX-7 (FD chassis) as a rolling shell with the K20Z engine swap already in it. The engine was already mated to a stock Honda S2000 six-speed manual transmission, so that took a lot of the legwork out of the swap from the get-go. However, in total, the car itself cost him a whopping $16,000.

But that made us wonder: How much would it cost to swap the K20 engine and S2000 transmission into an FD RX-7 empty shell?

Finding an RX-7 shell could be the hardest part

Ben was pretty lucky that he found the RX-7 shell with the K20 engine swap already in it. If you’re planning to take on a project car endeavor like this, then you’ll need to find a 93-95 Mazda RX-7 shell first. Doing so can be tricky, considering the market for these cars has risen a lot in the past decade, and finding an actual shell can be tough as well.

However, if you happen to find one, then you can expect to pay anywhere from $10,000 to $15,000 depending on the car’s condition. We weren’t very lucky in our nationwide search for one using Auto Tempest, however, we did find a couple of complete 1995 RX-7’s selling for around $25,000. Just remember, this step could take a while.

Sourcing a K20 swap is easier but still pricey

Next, if you’re able to find an FD RX-7 as a project car, or if you already have one, then you will need to find a Honda K20 engine to swap into it. Fortunately, these engines are prevalent all over eBay and Craigslist, so finding one won’t be too hard.

As far as cost goes, depending on which engine go with, it could cost you anywhere between $1,000 and $2,000 for the engine alone and another $1,000 for the S2000 manual transmission. Then there’s the cost of mounting and wiring everything to the chassis.

For this type of swap, you’ll need a custom adapter to mount the transmission, which will cost around $300, in addition to a custom flywheel that costs around $600. And we haven’t even gotten to all the wiring, custom axles, and driveshaft yet.

All of that hardware could easily cost another few thousand dollars depending on who does the work for you. Ultimately, while the engine swap will cost a lot of money and effort, it could eventually be worth it.

Why would anyone want to swap a K20 engine into an RX-7?

Reliability is at the top of the list when it comes to doing this engine swap. According to Ben from Gears and Gasoline, swapping a Honda engine into an RX-7 should lead to fewer repair and maintenance costs down the road to the point where the owner might actually break even with the initial cost of the swap. Although, it could take a really long time to make the cost of entry worth it.

Ultimately, Ben’s K20 engine project cost over $60,000 in total, with $20,000 of the cost going to labor. Keep in mind that his project included a whole turbocharger system, which made the swap produce over 400 hp. But if you’re planning to undergo this type of project yourself, you could possibly complete it for cheaper, albeit not by much.