Original small block “rams horn” exhaust manifolds (produced up to 1979) can be said to flow efficiently. Their flow may not be optimal, but they are better than many of the original equipment manifolds. The idea is to reduce back-pressure while tuning the flowing exhaust gases. The center exhaust ports on the OE cast iron manifolds dump into a rectangular box that the outer cylinder exhaust gases flow into. This mixing of exhaust gases so close to the cylinder head and exhaust valves hurt engine performance from lack of flow.
1965-1982 Corvette disc brake systems were a major technological advancement at their onset. The C2/C3 Corvette design utilized “fixed” disc brake calipers. This same “fixed” design disc brake caliper was used on GMs other than Corvette high performance vehicle line-up in limited quantities during 1965-1968. When disc brakes became commonplace in 1969, “floating disc brake calipers” were used. Floating calipers slide on a ways system, repositioning the caliper as the disc pad wears. This sliding or floating caliper proved to be a good thing, allowing for discrepancies that the fixed caliper would not compensate for. From 1969 on, the majority of vehicle manufacturers used floating disc brake calipers for easy serviceability, while GM utilized the early style fixed calipers on the Corvette until 1982. There was a J56 brake option for the fixed disc brake calipers consisting of heavy duty semi-metallic pads and two pins to retain the pads. In addition Inconel steel reinforcements were placed on the caliper mounts to the spindle to prevent caliper flexing under severe braking. Good stuff but hard on brake rotors you can expect to replace more rotors than the unique J56 disc brake pads. Another downside was the J56 brake option required heat to build before they worked well and with less effort. (more…)