1955 Mercedes-Benz 300 SL Alloy Gullwing (chassis 5500189)

Steel Gullwings are scarce by ordinary sports-car standards. Aluminum Gullwings are a different species. Mercedes built the competition-oriented alloy package — lighter shell, hotter cam, lower springs, wider race rubber, Plexiglas, vented drums — for customers who would actually race the road car. Public factory tallies cited across specialist literature put production at 29 alloy bodies, roughly two percent of Gullwing output.

Chassis 5500189 is the third of those twenty-nine. Gooding Christie’s Retromobile New York catalog records the origin story that matters: Mercedes-Benz of Hollywood steered young Lance Reventlow and Bruce Kessler to the San Francisco warehouse with instructions to pick the silver car a magnet would not stick to. They took 5500189 south, painted it dark blue metallic for the season, and campaigned it through late 1955 and into 1956 — Salinas, Torrey Pines (including Kessler’s overall win), Glendale, Palm Springs — before Reventlow moved on toward the Scarab chapter that would define him.

After the race season the car passed through documented Pacific Northwest and European hands (Fodor, Hamilton, Waschke, Winkler, a Swiss collection, Dennis Daugs with Rudi & Company returning German Racing Silver) and has spent roughly sixteen years in a southern US private collection. Catalog diligence flags an early engine history note: the present unit carries date codes and a restamp story that a buyer must verify with a 300 SL specialist — significance here is alloy identity and period Reventlow/Kessler use, not a blank originality claim.

Score 93 — Ultra-rare. Path B (documented competition/alloy package of 29 — clears ≤200; not Path C, which caps short series at ≤25). Specification is the correct lightweight Gullwing package; Reventlow/Kessler period race use and continuous known history are exceptional; public appearances of alloy cars remain rare. Engine restamp history is a diligence haircut, not a kill. Estimate $4–6M, Rétromobile New York, 20–21 November 2026.

Watcher’s checklist

1. Confirm chassis serial 5500189 and alloy body identity (magnet / specialist inspection). Gooding lists type prefix 198.040; Gull Wing Group literature uses 198.043 for aluminum shells — reconcile with factory records / club desk.
2. Review engine 198.980.5500210 history against the catalog’s restamp note — get a 300 SL desk opinion.
3. Separate period 1955–56 race results from later ownership cosmetics (blue season paint vs DB 180 silver).
4. Verify Rudge wheels, concave-star grille, and luggage set as catalogued.
5. Link out only to Gooding’s lot page.
6. Rare Machines is editorial — we do not inspect, authenticate, or broker; confirm everything with the venue and your own diligence.