Tue May 13, 2014 5:06 pm by nialloftara
Emissions will have a huge range depending on the year the engine is made in, anything on leaded fuel isn't even counted. With my company I set my limits at 3000 in 72, 1300 with manadatory converters in 74, 900 in 83, 700 in 87, 600 in 91, 400 in 97 and 200 in 01 for production engines. these vaguely line up with the dates for the energy crisis, the advent of the catalytic converter, the American CARB standards, and various federal regs and laws for clean air and auto emissions, again that's in the US and only arbitrary numbers I picked for each. top 4 reductions are three way catalytic converters, fuel injection type (mpfi or DI), pistons type (hyperpneumatic or low friction) and then block and head material, aluminum is better then iron. hope that helps.