Best of luck with the smog test. Set an appointment, and get the new engine oil good and hot. Lots of smog test centers got rig of their ability to test OBD1 or earlier vehicles. the remaining have raised their prices. Offer to take off the engine covering and have it off to the side, so the tech does not have to do it. They charge extra for vans because of the engine cover potential pain in the ass removal and return time consumption.
Also make sure the battery is totally and completely charged, so it cant accept much amperage from alternator, atwhatever voltage the regulator is commanding, and increase load on engine during the roller/sniffer test.
Running some gumout regane or redline SI-1 through less than 15 gallons before the smog and oil change will likely help it run cleaner.
Would love to see pics if you fabricated new Air hoses. Mine are all beat up, and perhaps restrictive or allowing some
warmer underhood air into the tube than there should/could be.