Just like you wouldn't attach sturdy table legs to a flimsy tabletop, it makes no sense to bolt a state-of-the-art aftermarket suspension system to a floppy chassis. Unless a car's chassis is stiff enough to endure the immense cornering loads that modern g-Machines can produce, the countless R&D hours a bunch of smart engineers invested in improving suspension geometry, revising camber curves, increasing roll stiffness, and optimizing shock valving all go down the toilet in one expensive flush. With the groundbreaking aluminum front suspension and four-link rear suspension Detroit Speed and Engineering (DSE) recently launched for 1964-70 Ford Mustangs, it's hardly surprising that DSE also designed a set of matching subframe connectors.
To put the importance of a stiff structure into perspective, consider that the typical unibody chassis of the muscle car era was only designed to handle 300 or so gross horsepower on skinny bias-ply tires. In contrast, modern Pro Touring rides often crank out upward of 600 net horsepower, and stick it to the pavement with sticky R-compound tires exceeding 300mm in width. Putting that much power and grip through an unfortified unibody will twist it up like a wet noodle in no time, which is why subframe connectors are such essential pieces of hardware. By tying the front and rear subframes of a car together, they help a unibody chassis mimic the stiffness of a full-frame car.
While that might sound like a great deal, installing subframe connectors certainly has drawbacks as well. Running a long piece of round or rectangular tubing beneath the entire length of the floorpan can compromise ground clearance, and on g-Machines that already sit low to the pavement, that's a very bad thing. Likewise, unsightly bracing hanging down below the rocker panels flat-out looks ugly. Not surprisingly, DSE wasn't OK with this either. Never a company that cuts corners, DSE put forth the extra effort to design its Mustang subframe connectors the right way, not the easy way. In contrast to a more typical subframe connector setup that hangs way low, the DSE protrudes through the floorboard and into the cabin at the rear seat footwell area to maximize ground clearance. Part of what makes this possible is a custom DSE torque box that serves as an anchoring point for the rear of the subframe connectors. Although this arrangement does require a fair amount of cutting and welding, the payoff is a superclean install without any compromise in ground clearance. DSE installed one of its new subframe connector kits on its 1965 Mustang fastback project car, and we wanted to be the first to document the process.