The Bradford-based business, owned by the Tordoff family, reported strong demand across all its brands, which range from Aston Martin to Vauxhall.
John Tordoff, chief executive, said: “We’ve had a great start to 2014 after seeing an encouraging recovery last year with our best-ever September and it’s fantastic that the upturn in consumer confidence is building.
“There’s no doubt that as the economy continues to recover, there is a pent-up consumer demand with customers who had delayed changing their car now deciding that the time is right.”
JCT600 announced the acquisition of Sheffield-based Gilder Group from its outgoing chief executive Garry Scotting in March 2013 for an undisclosed eight-figure sum.
The deal included nine of Gilder Group’s car and commercial vehicle dealerships, two parts depots and a body shop.
The Competition Commission cleared the deal in September.
The acquisition of the Gilder Group is expected to take sales towards the £900m mark, making JCT600 the region’s biggest family-owned business by some margin.
JCT600 has 47 dealerships and 1,800 staff.