He returned to prototypes in 1984 but had little success at that level and retired after the 1989 24 Hours of Daytona. He then competed in select vintage races in the same 1969-model Eagle racing car in which he won the 1969 SCCA Continental Championship. The car is now owned by Doug Magnon, the founder of the Riverside International Automotive Museum, and prepared by mechanic Bill Losee. It bears the identical livery it carried back in 1969. As the Eagle had been parked immediately after the 1969 season, and was not run again until following its restoration in 2008, Adamowicz remained the only driver to actually have driven this car.