73 EGR Question

no you don't need the egr. egr stand for exhaust gas recycled.when smog came on strong in the early 70s they made the carb very lean to help control smog. the buy product from this is very high combustion heat which causes nox gas. a green house gas that al gore is so bitter about.this high combustion heat is also the reason the factories reduced the compression on are muscle car engines. buy mixing in a inert gas such as exhaust gas witch has very little oxygen due to combustion, it lowers combustion temp thus reducing nox.it worked out ok also because the temps of combustion from being so lean would also burn exhaust valves and so it helped here to. the good thing is at wide open throttle there simply not enough manifold vac to open the valve so it didn't effect the performance of the engine at least in wide open. and the carbs were set to richen up at wide open also.now days the fuel injection and computer control egr devices and catalytic converters have allowed compression to come back to some extent. bottom line its not needed for performance over all, the engine is more friendly without it at least in a driving way