1965 Chevy Impala SS409
Car and Driver (December 1964) noted that things had changed but stayed the same since the early '60s when the Beach Boys first sang "She's real fine, my 409." Engine displacements of over 400 cubes had been non-existent only half a decade earlier, but then 406-, 409-, 413-, 425- and 426-cid motors had come along, consistently upping the ante for high-performance fans.
The 425 "porcupine-head" big block proved to be nearly a Chevy pipe dream, because after it put in a quick showing at Daytona in 1963, GM brass told all divisions to get out of racing and throw all their racing hardware away. Thus, the 425 became known as Chevrolet's "mystery engine."
As a result of this change, the 409 found its way to the top of the bow-tie options list again when the all-new '65 Chevys arrived. Chevrolet's full-size 1965 model was curvier and larger than its counterpars of 1963-1964. It gained nearly 4 inches in length, although using the same 119-inch wheelbase. Curb weights rose more than 125 lbs. over 1964 for most models. The fact that the new Chevys were larger was a good reason for adding the 409 engine.
For the first time this year, Impala SS models were in their own separate series. The V-8 sport coupe sold for $2,947 and weighed 3,570 lbs. The counterpart convertible was priced at $3,212 and weighed 3,645 lbs.
The 409-cid V-8 came in 340- and 400-hp versions. The more powerful one was available with a Muncie four-speed manual transmission. It had an 11.0:1 compression ratio. However, the 340-hp engine was a better seller by far and is the one that Car and Driver tested. This engine featured a single four-throat Rochester carburetor and a 10.0:1 compression ratio. In the 4,200-lb. test car, it provided .083 hp per pound.
Equipped with a Powerglide automatic transmission and 3.31:1 final gear ratio, the 340-hp Impala SS sport coupe did 0-to-60 in 8 seconds flat. It took all of 16.4 seconds to scoot down the quarter-mile at 91 mph.