He graduated High School in 1945, then enlisted in the US Army for a two-year stint, during which he was stationed at Fort Carlson in Colorado.
[6] To earn a living he worked as a plater of baby shoes, a credit manager for a Chevrolet dealer and a railroad telegrapher for Union Pacific.
[6] He built his car with an engine and chassis from an MG and bodywork of 0.019 in (0.5 mm) thick aluminum paneling that was screwed in place to a framework made of welded electrical conduit.
In 1956 Kastner moved with his wife and two children to California, where he went to work for Williamson Motors in Los Angeles as a mechanic.
While still racing his MG-powered Special, Kastner went to work for Cal Sales, the Triumph distributor for the Western United States, in Gardenia, California as a mechanic.
Kastner continued to race, winning the 1959 Class E Championship with the California Sports Car Club and the SCCA national title.
Kastner and Dean Moon collaborated to develop a camshaft profile able to provide 150 hp (111.9 kW) with the factory SU carbs.
[7]: 1 [6] In 1963 Kastner took three factory stock TR4s, prepared them, and took them to the 12 Hours of Sebring, where they finished first, second, and fourth in the 2.5 GT class.
Triumph countered Shelby by offering to match the salary if Kastner would stay to establish and run a new US competition department.
[9]: 115 The car had an all-aluminum tub, a single seat with a cover over the passenger's area, a head-fairing behind the driver and a Le Mans nose.
In 1966 the car was sent to California, where Kastner substituted a 200 hp (149.1 kW) 2 L inline six and a TR4 transmission, added a larger radiator and fuel tank and modified the hood with a scoop to clear the longer engine.
Kastner prepared a special "Super Stock" TR4A with fiberglass body panels and alloy wheels that helped reduce total weight to 1,700 lb (771.1 kg), and added a 160 hp (119.3 kW) engine.
[14] This car received a full-width roll-bar, heavy duty springs, shock absorbers and axles, and a locked differential.
The engine was bored out to 87 mm (3.4 in) to increase displacement to 2,187 cc (133.5 cu in), and was brought to the same level of tune as the Sebring cars, producing just over 140 hp (104.4 kW).
At the Bonneville Nationals that year the car beat the previous record, but was in turn bettered by a tuned Daimler.
Kastner went to Triumph headquarters in Coventry to pitch a project for a new aerodynamic race car to run at Sebring.
[9]: 118, 119 Reportedly all Kastner took with him was his reputation, a promise of a magazine cover page, and a single rough drawing done by Pete Brock, designer of the Shelby Daytona coupe.
The car, christened the TR-250K, was based on a standard Triumph independent rear suspension chassis, but with a tubular structure added to support the alloy bodywork.
The aluminum bodywork, just 0.050 in (1 mm) thick, was strikingly sleek, and included a movable rear spoiler to control down-force.
Targeted at SCCA C-Production class, the TR-250K was raced at Sebring in 1968 but retired when a rear wheel, which had come from a Chaparral and had been machined to fit the Triumph hubs, broke and damaged the suspension.
The car debuted at Road America, Elkhart Lake, Wisconsin on 17 July 1971, where it finished in eleventh place and earned a single championship point.
They also bought a Lola T192, which was first loaned to George Bignotti for the 1971 Questor Grand Prix, where it was driven by Al Unser.
[17] With sponsorship from Carling Black Label beer, Kastner led the team's efforts in Can-Am, Formula 5000 as well as three Indy 500 races.
Discussions with friend and early turbocharging expert Hugh MacInnes led Kastner to establish Arkay Incorporated in Hawthorne California.
[17] Arkay developed complete kits for aftermarket turbocharger installations for a wide variety of cars and engines.
At the time some of Nissan's upper management wanted to terminate the GTP program, which was operated by the Electramotive Team.