GM Radiator Insulators S.B. 68-87

The GM Radiator Insulators S.B. 68-87 by PROTHANE are essential thermal management components designed for small-block Chevrolet engines built between 1968 and 1987. As an experienced mechanic, you know that engine bay heat directly impacts fuel vaporization, ignition timing stability, and overall powertrain efficiency. These insulators work by reducing radiator-to-engine block heat transfer, keeping coolant temperatures more consistent and preventing hot spots that can cause detonation in high-compression or modified engines. Whether you're running a street machine, weekend racer, or daily driver with performance modifications, proper radiator insulation is a cost-effective upgrade that pays dividends in reliability and drivability.

PROTHANE's radiator insulators are engineered from high-temperature polymer composites that provide superior thermal resistance compared to traditional rubber or cork gaskets. The compact design—measuring 3.25 x 2.75 x 3.9 inches and weighing just 0.28 lbs—ensures a direct bolt-on fit with zero modification required. These insulators install between the radiator support and radiator core, creating an air gap that dramatically reduces conductive heat transfer from the engine compartment. The material resists coolant degradation, maintains dimensional stability across wide temperature ranges, and won't compress or deteriorate like softer alternatives, ensuring consistent performance for thousands of miles.

These insulators are ideal for any small-block Chevy owner looking to optimize cooling system efficiency and protect against thermal stress in high-horsepower applications. Installation is straightforward—remove the radiator, position the insulators on the support brackets, and reinstall; no special tools or cutting required. They're particularly valuable if you've upgraded your ignition system, increased compression ratio, or added forced induction, as these modifications amplify the need for precise thermal control. Compatible with all small-block variants (283, 327, 350, 396, and similar displacements), the GM Radiator Insulators S.B. 68-87 deliver measurable improvements in coolant temperature stability and engine bay climate, making them an essential addition to any serious build.