Recently I purchased this Rotary Engineering header for my 85 gsl. In the past someone has welded extra tabs onto the flanges. I would like to cut them off if they are not essential. Are these necessary for use on my 12a? Pictures are attached below. Thanks, Justin.

 

I've never seen that before, I don't know why they would be essential.

 

I first thought that hose tabs where most likely welded on for a person who was using these headers on an early 12a that originally had a thermal reactor (SA's 79-80 rx7's). But both of the tabs would need to be in the middle so that is not the reason for these tabs. The picture below shows the wholes that I'm referring to.

Maybe the previous owner was getting an exhaust leak toward that side because of the design of the header flange and thought this would help solve the problem. So they might be unnecessary for you but if you left them on I don't think it would hurt anything. Its up to you.

 

Two front thermal reactor rotor housings were probably in the previous engine, so he had to weld the tabs on. That makes sense to me.

 

Thanks all for the responses. As always, a plethora of information! I have never researched much about thermal reactors, but will get there some day if/when I get a SA. Pretty cool that these tabs can tell so much about the previous engine it was on. I am going to cut them off carefully to regain the symmetry of the flanges, rotary exhaust feng shui!