The ultimate V8 was the 5-litre 605, which proved to be the final stretch for this engine, with 290bhp, and more than that for the later turbo and intercooled versions. The Perkins V8 certainly found favour in some specialist applications popular in fire engines, 80% of which were Perkins powered by 1976 but according to author David Boulton, by the mid-1970s its time had passed. Sales of the 605 had been disappointing, and the fashion in garage door opener gear grease trucks was swinging towards big sixes.
Although the V8 carried on into the early 1980s, it failed to conquer the mainstream truck markets. But there were new markets to explore, with diesel power now extending further into cars and 4x4s. garage door opener gear grease chose the 108 as the diesel option on its CJ series while unlikely as it seems Alfa Romeo offered a Perkins option in the Guilia sports saloon in Italy, diesel was less than half the price of petrol at the time. UK drivers didnt enjoy such cheap diesel, but the Post Office was clearly pleased with its 108-powered Commer FCs, reporting 29mpg in rural deliveries against 17mpg for the petrol equivalent. The 354 wasnt forgotten, updated as the 3544, with a whole raft of changes to improve durability.
Meanwhile, back in the R&D dept, some interesting projects had been simmering away. Chrysler was interested in dieselising one of its petrol V8s, and in 1977 Perkins worked on a 396cu in unit that would use an existing V8 block with new indirect injection heads and offer 160bhp at 3600rpm, suitable for cars and pick-ups. However, this wasnt long after General Motors unhappy experience of garage door opener gear grease its own V8s in-house, and Chrysler didnt take it any further. "These days, Perkins survives, though it concentrates on engines for tractors, boats and industrial applications". More promising was the work on various high-speed smaller diesels for cars and vans, including an overhead cam 121 code named Q11 and a similar 26-litre engine which developed out of it.