Corvette Chassis History, Pt. 3: The C4 Chassis That McLellan Built
One of the C3’s endearing features was the T-top roof. The design wasn’t just for aesthetics; the T-bar connected the A-pillar windshield frame to the B-pillar frame “roll bar” and provided significant structural stiffness. The initial design of the C4 had a T-bar connecting the A and B-pillars, but with a one-piece, roof panel. It wasn’t until the first prototype was built in 1981, when Chevrolet general manager Lloyd Reuss made the decision to eliminate the T-bar to open up the cockpit. This single decision impacted the C4 design such that the biggest complaint about C4s is the tall side frame sills that make ingress and egress challenging. To compensate for the lack of the important T-bar, the side frame sills had to be made extra tall. As the years rolled by, C4s, especially the convertibles, took heat for not being as stiff as their competitors. Those two elements, plus the fact that progressive Corvettes kept getting better and better, are part of the reason why C4s are today the least desirable of all Corvettes.
