The road-holding was improved further when the 504 got independent rear suspension in September 1968. This was also Peugeot's first model with power assisted disc brakes on all four wheels. Customers for the 504 had a choice from seven four-cylinder power units. The motors had overhead camshafts with the smallest 1,796 cc producing 50 bhp and the largest 2,112 cc yielding 136 bhp. A 2,664 cc V-6 engine that produced 136 bhp was added in 1975. The new V-6 was a joint development with Renault and Volvo. Practical Classics August 2010 - Featuring Buyers Guide Peugeot 504 Coupe and Cabriolet (1969-1989). Click Here to view in our shop.