Chevrolet’s Hemi, the most potent and feared engine dropped into a “Bow Tie” product during the muscle car era, was the 409, evolved in December of 1960 from the W-series cast-iron V-8 originally introduced for 1958 Chevys. The new 409 could be had with several levels of equipment and in various states of tune, all of the way up to the so-called “409/409,” which was factory-rated at one horsepower per cubic inch of displacement. This fearsome engine, with dual four-barrel carburetors, made for a rowdy quarter-mile competitor, particularly when installed in the Impala SS hardtop.

The Impala SS offered from the Mohrschladt Family Collection was built at Janesville, Wisconsin, and delivered new in Omaha, Nebraska. According to information received by Mr. Mohrschladt, its first three owners were all friends in Omaha, accounting for the car remaining in that city until 2000. The third owner bought the car in 1993, and began a frame-off restoration to original condition, completed in 1997. It was both improved and highly detailed for authenticity by the fourth owner, performance Chevrolet aficionado Doyle Groat, who acquired the car two years later.

Mr. Groat exhibited the car at the Late Great Chevys Midwest National in 2002, scoring 987 out of a perfect 1,000 points—one of reportedly many awards achieved in his ownership. Mr. Mohrschladt acquired the car in 2007, making it one of the longest-term residents of his collection, and is believed to be only the fifth owner.

Examination of the car’s numbers is thoroughly satisfying, with numbers of all major mechanical components properly date-coded to early 1962. The car’s body tag decodes to it having been built in late March, while the engine is a proper 1962 409 block, casting code number 3788068, date-coded A2562 with a T0552QB stamp, indicating it was built on 25 January 1962 but installed on 22 May 1962, with dual four-barrels (a 409/409) and manual transmission. As with most Chevrolet muscle cars, definitively proving the originality of the 409/409 to this car is difficult, but one of the carburetors is date-coded April 1962, indicating that production of the car may well have been delayed until the spring—hence the relatively late installation of a January-built engine.

The trim codes of the original body tag decode to Tuxedo Black finish and red vinyl SS bucket seats, both faithfully duplicated on the restored car, which retains consistent showroom-quality chrome trim, great panel fit, and very good paint finish, as well as an interior that shows only light age and wear. The odometer shows 5,490 miles at the time of cataloguing, obviously the gentle and appropriate mileage since restoration.

An impressive “409/409,” this amazing beast would be a star of any collection of great American muscle.