A works prototype 1964 Porsche 904 is valued at £1.1m-1.3m ($1.7m-2m) ahead of Coys' True Greats auction in London on December 2.
Porsche designed the car as a GT for use in endurance racing and released it to the public in a limited run to meet the rules on homologation.
 The Porsche 904 works prototype was designed for road racing |
It was competed in a number of high profile races in the year it was built, including Sebring, Le Mans and the Tour de France - where it finished first in its class.
The 904 went on to become hugely popular and remains among the most desirable models of all time.
Coys comments: "This 904 remains one of the finest and most successful Porsches ever constructed. It kick started a program of racing cars, that would eventually result in the all-conquering 917.
"It also holds a unique spot in the manufacturer's history as the last dual-purpose sportscar Porsche ever built."
A 1964 Ferrari 275 GTB is likely to prove another highlight with a similar estimate of £1m-1.4m ($1.5m-2.1m).
Coys comments: "To many cognoscenti the 275 is the finest of all front-engined Ferraris.
"Its luxurious interior shows Ferrari production cars had matured yet its performance is comparable to a 250 GT SWB and its handling and brakes are superior."
Earlier in the week a 1965 Ferrari 275 GTB made $2.1m in Mecum Auctions' Anaheim sale.
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