1974 225 Emissions questions

The choke timer is good for opening the choke faster, so you don't run rich. EGR will generally make the engine run worse, even when working perfectly. EGR reduces NOx, which is beneficial in crowded areas w/ stagnant air (L.A. Basin), but won't hurt anybody in Seneca and is no long-term threat to the earth's air. Keeping EGR will lower your mileage, giving more CO2 emissions, which is a long-term threat (google "Al Gore"). A block-off plate is $15 on ebay. Very hard to insure any of the vacuum emissions controls are working today, and nobody should expect you to do so. Best long-term is to replace the carburetor w/ fuel injection, w/ throttle-body being the only bolt-on option for a slant and requires a 4-barrel intake. One TBI system is now under $1000, w/ used kits much less on ebay.