If you’re reading our magazine, chances are you know two things to be true. For starters, you know LS swaps are pretty awesome most of the time. Following suit, you know that LS swaps are extremely popular, especially when swapped into platforms which were originally never designed to house a pushrod V8. Here we find ourselves gazing upon this LS6-powered 2004 Mazda RX8; dreams coming to fruition.
Brought to us by Bring-A-Trailer, this LS-powered Japanese coupe is currently up for auction via the online car auction, and it’s surely one you won’t want to miss. According to the original ad, the car was built to showcase the capabilities of a Katy, Texas, shop called HP Motorsports. In the video above, the team demonstrates the effort put into this LS-powered RX8, and it wasn’t easy.
Matthew, the owner of HP Motorsports, provides his input on the build as the head of its funds. “We were all just sitting around thinking of something cool to do as a project for the shop, mainly to show what we are capable of. Sergio had this idea of putting a big American V8 inside of small Japanese car…”
Sergio’s role, besides helping to concept the idea for the build, was to ensure the engine would fit inside of the car from the get-go. For anyone who is unfamiliar with the Mazda RX8’s original powerplant, this Japanese coupe came with a 1.3-liter rotary engine from the factory; no pistons there, folks. So, one could imagine having to try and fit a round peg into a square hole, so to say…

The new (allegedly) 6.0-liter LS6 V8 fits quite nicely after a few modifications under the hood of this Mazda RX8.
Like most projects, the HP Motorsports’ Mazda RX8 did not come to fruition so easily. From the allegedly bored LS6 engine (from 5.7- to 6.0-liters according to Bring-A-Trailer, though we’re not sure how they accomplished that since you can’t really bore an LS6) to the T56 six-speed manual transmission, and everything in between, every input on the car had to be done custom.
“…it was like trying to fit a puzzle piece,” said Santiago, one of the techs at HP Motorsports. “You’ve got to measure and make sure that, when the body comes down, that the subframe fits underneath.”
AJ, another one of HP Motorsports' fabricators, was tasked with handling most of the custom fab work for "JAPICAN", the LS6-powered Mazda RX8. He completed a fully custom exhaust, along with that trick bright red SFI-approved roll cage in the interior, which we think sets off this RX8 quite nicely, and keep things legal around the road course, too.
“I did all of the custom work,” AJ detailed. “I had to cut the frame out to fit the engine, but the roll cage was probably my favorite part; it was all my idea and my fab work, so it was pretty fun.”
Thankfully, all of the difficult (and expensive) legwork is already done on this Mazda RX8, and you could be rolling around in a 433 RWHP LS-powered Mazda RX8 for much less than the build price, about $35,000 in parts and labor, according to the original ad. For more information on this LS6-swapped Mazda RX8, check out the listing on Bring-A-Trailer here.