Whats the difference between the 30022 and 30018? Can i use a 30022 on an '87?

 

I don't know the what the diffence is, but I used P/N 30018 on my SLP 30001 1 3/4 headers. My car is 87 IROC, if this helps.

 

According to their catalgog, they are both the same except 30018 includes a modified AC bracket (for the 82-87 cars).

Mine's an 89 so I don't know what they modified on the bracket. I imagine you could figure it out once you get on there and modify it yourself (if you still have your AC).