NUT, Mazda exhaust manifold, 1990-05

We typically reuse these, but if your car is especially old and/or these nuts have been on and off many times it’s a good idea to replace them. The harder you drive your car (e.g., track use), the more important it is to replace these. Better safe than sorry! 

Factory part B6S7-13-465. From a 90-93, but works for all 90-05s, including the MSM. This is a heat-treated nut specifically for exhaust applications, the later part (9994-61-000 for 1994-05) is a generic lock nut. We don’t typically see issues with either, but it’s always best to use the best parts possible, especially with turbo applications – i.e., high exhaust heat / metal temperatures. 

Nine needed per engine, sold individually.