Hello, I have a set of Mac headers with their "Y" pipe that has been for a couple of years. At stops with air or heater on, i get a exhaust smell inside and my car has a bad exhaust smell outside--hate to pull into a drive thru. Looking on my driver side it seems to be black soot on my wires,plug in the middle. I fiqure(think), i got a leak where the header, heads meet, no exhaust leak sound. Back when Mac headers were the talk of this site, they said that the stock GM gaskets were the best,(That what i used) or Felpro 1406--What do you guys suggest now that would be better?. Is this going to be a kinda easy job, just back off ths header and replace? I used the stage 8 locking header bolts.The shop who did the intial install used red sealant, i can see it around the gasket. Did a serch but needed newer help. Thanks Dwayne

 

You'll get varied responses about this. Me personally, I went with the Fel-Pro 1406s with my header application and they have worked flawlessly.

 

Thanks for your reply, yeah back when Macs were the ones to get, it was either GM stock or Flepro 1406-I went GM--Why would they use red silicone? Warped headers flanges or just to keep them lined up? I guess it could be either--Is this a normal wham bam thing,just to take off the bolts, back off header on driver side,clean silicone,replace gasket tighten up my Stage 8 bolts?? Thanks again Dwayne

 

I would imagine the silicone was there to hold them in place, but wouldn't be surprised if it were there for sealing purposes as well. I ended up giving my Fel-Pros a coating of the Permatex Copper Sealant in the spray can to aide in sealing. They can be a royal pain to keep in place while trying to get the header and gasket aligned and then the bolts in place. That could also be the reason why the silicone is there.

 

I used Percy's Seal 4 Good Dead Soft aluminum gaskets. From what I could gather when preparing for my header install, they seemed to be well regarded.