Fred is bang-on. I have an original mailer from our local Chevy dealer from '70 that covers the new emissions tech. The charcoal canister schematic is shown over a Monte Carlo silloette. I was California only for '70 & 49 state in '71. I don't recal our '74 having such a system though. As far as a replacement charcoal canister, I've never seen anyone advertise them. I wonder if dealers could still get them?