In spite of a successful match racing season, the arrival of Mercury and Ford's new Logghe tube chassis, flip-top fiberglass Funny Cars, and their 427 SOHC V-8 engines placed the S&M Barracuda at a disadvantage. Ironically, it was old rival Don Nicholson that led the charge when Don's revolutionary new Funny Car won heavily in both 1966 and 1967. Sox & Martin continued to soldier on until 1967 when Chrysler's drag racing brass called a halt to the Funny Car program.

In 1967, Ronnie found himself back at the wheel of an 11-second, four-speed, full-bodied race car, which he adapted to with immediate success. Along with the more docile Super Stocks came the immensely popular Performance Clinics. Sox & Martin carried the banner for the Plymouth Division on the East Coast, while Dick Landy was their West Coast counterpart for Dodge Division. Staged at dealerships, the clinics lured new customers into Plymouth and Dodge dealers by teaching basic as well as advanced drag racing techniques. The clinics covered engines, tuning, chassis prep and tuning, and driving tips, all from the well-traveled, well-schooled clinic stars-Sox & Martin. New car dealers loved the clinics, and reportedly sold thousands of cars as a direct result. The clinics also enhanced awareness of drag racing and increased attendance at local tracks. It was a win-win situation all around when the S&M hauler ramp truck and second race car on an open trailer parked in front of a local Plymouth dealer's showroom. Sox and Martin were the epitome of professionalism for a race team. They dressed in matching uniforms and handled questions with articulate aplomb, capturing legions of fans for Chrysler vehicles and Mopar Performance parts.

Chrysler's two divisions liked the race results and sales they were generating with their drag racing programs. Bolstered by this success, they placed their engineering focus on creating vehicles, parts, and support that would dominate drag racing. When R&D and testing efforts were complete, Chrysler contracted Hurst Corporation to build a short production run of 426 Hemi-powered '68 Dodge Darts and Plymouth Barracuda coupes. Hurst set up a line in the Detroit suburb of Royal Oak and began assembling the all-time baddest production-built vehicles ever offered to the American public. The 426 Hemi Barracudas and Darts were instant legends, claiming loads of Super Stock class and Super Stock Eliminator wins at national and regional events, as well as local tracks.

These street missiles featured the heavy-duty Dana 60 rear axle for stick-shift cars or an 831/44 axle for automatics, a heavy-duty New Process four-speed gearbox or 727 Torqueflite automatic, a thoroughly engineered cross-ram intake manifold carrying a pair of Holley four-barrel carburetors, and a gigantic hoodscoop designed to intimidate the competition, as well as ram cold air to the sealed inlets of the carbs. Factory compression ratios for the Race Hemi 426 were quoted as 14.0:1, and the cylinder heads came with sizeable intake and exhaust ports more than capable of allowing the engines to be revved at 8,000-plus rpm. It was a skillful job of total overkill, and an example of the powerful strength of a vehicle company when it chooses to create a winning racing program.