I ran into the same exact problem with my 87 a couple of months ago. I ended up replacing my cat with one I purchased from checker auto for $70. They actually sell one that is Toyota specific and has the bolt on flanges already attached, so there is no welding needed. After install, I re smogged and it passed like a new car literally! One part of the test I had to score a 220 or below and it was failing at a 2100! After install I passed with a 4! If you go to the checker website, You should find what you need.