This slicktop 1980 BMW 635CSi is a European-market example that was refurbished before being sold through by Oldenzaal Classics and imported in 2025, after which it was fitted with an S54 3.2-liter inline-six and six-speed manual transmission by Lang Racing Development. The engine installation included rebuilt cylinder head and VANOS components, new timing-chain components, oil pump and bearings, fabricated engine mounts, headers and exhaust, a custom intake, and associated wiring and control hardware. The drivetrain uses an E46 six-speed transmission, a limited-slip differential, and a custom M3 driveshaft. The car also features 15″ BMW Style 5 wheels, a decklid spoiler, fog lights, European-market lighting and bumpers, power windows, and power locks. Now with an indicated 147k kilometers (~91k miles), this E24 635CSi is now offered on dealer consignment with a clean Oregon title.
The selling dealer believes the exterior color is Graphite Metallic/Graphit (087), and the car features fog lights, decklid spoiler, and twin center-exit exhaust outlets. The seller notes chips and blemishes in the paint, and European-specification lighting and bumpers have been retained.
The 15″ BMW Style 5 wheels are mounted with 225/60 Maxxis Premitra 5 tires. Recent brake service included rebuilding the front and rear calipers, replacing the brake hoses, flushing the brake fluid, and machining all four rotors. The power-steering pump was also replaced in May 2025.
The on-board check controls are located to the left of the column, and the car has both power-operated windows and locks. A radio blanking plate has been fitted, and the car is equipped with air conditioning. In September 2026, the passenger seat and door pocket were repaired, and the leather was refreshed.
The four-spoke steering wheel fronts a European-market instrument cluster with a 260-km/h speedometer, tachometer, and gauges for fuel level and coolant temperature. The six-digit odometer shows 147k kilometers (91k miles), with fewer than 200 miles added under current ownership.
The S54 3.2-liter inline-six was installed in 2025 by Lang Racing Development following the car’s import from the Netherlands. The engine work included cylinder-head machining, 87.25mm bores, new pistons, timing-chain components, oil pump, crankshaft and rod bearings, VANOS seals and related components, a rebuilt VANOS unit, and fabricated engine mounts. The swap also incorporated a used DME, engine wiring harness, throttle body, air conditioning compressor, alternator, belts, tensioner and idler pulleys, fabricated headers and exhaust, a custom intake, and associated hardware. Recent service included oil and filter replacement, valve adjustment, fuel and air filters, distributor cap and rotor, spark-plug wires, spark plugs, partial fuel-hose replacement, thermostat service, and air-conditioning system repair and servicing.
Records associated with the ~$39k swap are detailed in the gallery.
Power is routed to the rear wheels through an E46 six-speed manual transmission and limited-slip differential. The transmission was resealed and fitted with a clutch cylinder, while the conversion uses an E46 clutch and flywheel and a used M3 driveshaft. Differential mounting and bushing components were also serviced.