By Dean Larson

Photos: Seller, eBay

Porsche has been building 911s continuously for 56 years now with very few deviations in its basic design. But then again, why mess up a good thing? And the 911 is a very good thing, in every iteration ever built. But if you had to name one 911 as the definitive 911 in terms of looks and performance, which would it be? For many, the answer comes down to a simple three-letter designation — RSR.

Porsche’s new 911 made a huge splash on the touring car scene in 1970 and ’71, winning the Daytona 6 Hours, the Sebring 12 Hours, the 1000 km Nürburgring, and the Targa Florio. But Porsche proved they were only getting started by debuting the 2.7-liter RS (for Rennsport, race sport in German) in 1973. It featured a 210 hp engine with Bosch mechanical fuel injection, revised suspension and larger brakes. It also became instantly recognizable for its ducktail spoiler and larger rear wheel arches to accommodate more rubber out back. Porsche built around 1,580 Carrera 2.7 RS models for homologation in FIA Group 4 racing.

But somehow Porsche had even more tricks up their sleeve, and threw every conceivable upgrade within the rulebook at the ’73 2.8 RSR. Porsche somehow found another 176 pounds to cut off the already light 2.7 RS, which featured thin-gauge steel in the body and thinner glass. Other attributes of the 2.7 RS were enhanced even further in the RSR, including even wider wheel arches, a lower front air dam with an oil cooler and ultra-wide Fuchs wheels. A new and incredibly effective braking system was designed as well, which used components from the 917.

From there, Porsche engineers found room for another 119 cc, bringing total displacement to 2,808 cc. In addition, the 2.9 RSR received larger valves, a twin-plug ignition and a bump in compression for a total output of 300 bhp.

Only 55 2.8 RSRs were built, and they were incredibly expensive when new. Today, legit RSRs are true million-dollar machines, and they don’t come up for sale often, all of which explains why someone would undertake the ambitious 2.8 RSR tribute build we see here on eBay.

It’s based on a ’73 911T tub with steel front and rear bumpers and an aluminum hood and ducktail spoiler added. The chassis features RSR-style strengthening, and RSR front suspension. Brakes and rear trailing arms were sourced from a 930 Turbo, and the front air dam features an RSR-style oil cooler. Power comes from a 350 hp, 3.5-liter Rothsport engine with a custom Rothsport exhust.

Finishing the car off is a custom paintjob by Freeman Thomas, which honors the sensational “Hippie” Porsche 917-021 racer. The design was drawn by hand, and there were no decals used.

This 2.8 RSR tribute car has to be one of the most radical air-cooled custom Porsches available today, but at $450,000, it won’t come cheap. See it here on eBay.