Are there ANY smog legal headers for use in Calif? I have a 91 Suburban(the last year of that body style - suburbans changed in 92) with a 454. I had smog work done and it came back puffing of the left side. I am afraid that the manifold is cracked. If it is, I would be interested in calif legal headers. The can be a pia, and you need to have header bolt head clips(they keep them from turning) When i had my 69, I was forever changing out gaskets.