Some Years Ago, Chevrolet Began Lowering Engine Compression (To 8.50:1) In An Effort To Meet Tailpipe Emissions Numbers. It Also Retarded Camshaft Timing In An Effort To Lower NOX (Nitrides Of Oxygen/Unburned Particulates). By 1974, Horsepower, Torque And Overall Engine Efficiency Had Dropped Some 30 Percent To 50 Percent. Chevy’s RPO L48 And LM1 350 Small-Block V-8s Then Got A Flow-Restrictive Catalytic Converter In 1975, And Finally In 1985, A New Monolith Catalytic Converter, As Well As Direct-Port Fuel Injection And Improved Camshaft Timing, Boosted Horsepower, Torque And Engine Efficiency.