[5] In 1961, the Canadian Sports Car Championship (CASC) was founded,[6] in which Heimrath was able to secure the title with a Porsche 718 RS 60.

[7] He competed regularly in CASC championship races in the following years until 1967 and was able to repeat this success in 1964 with a Cooper T61M Monaco.

[10] In the following year he switched to a Porsche 911 Carrera RSR and drove there successfully in the GTO class until 1976.

At the 6-hour race in Mosport in 1977, which was part of the Trans-Am and the World Sportscar Championship, he achieved overall victory together with Paul Miller.

[12] From 1978 to 1980, Heimrath drove a Porsche 935 in races for the Trans-Am and IMSA championships and was able to achieve several victories in addition to good placements.

[15] In the following year, Heimrath drove in the Canadian Porsche 944 Cup championship and achieved eighth place in the season result.

[16] In 1997, he started with a Porsche 968 in the Canadian GT Challenge Cup in the GT2 class and won the championship straight away.