I've been getting the p0420 code so I am replacing the cats. I am looking at part numbers 23344 and 23345 from Magnaflow since they are direct replacement cats. I will be getting headers too.

There might be a few problems though. The studs going into teh heads look like crap. The nuts look like ***** for rust now. Will the bolts that comes with the headers be fine if they come with any at all? I am going with JBA. Do you think a good exhaust shop will be able get the studs out without breaking them or having to remove the head? I have a tight budget as it is.

I am also debating about what to do for the rest of the exhaust. I want it deep and loud. Should I stick with true duals or go back to SI/DO? I like the duals out the back but it is PITA to do a custom mandrel bent system due to parts availability. I also thought about duals out the side like the Lightning has. The problem there is trying to get it to work without having extremely tight bends. Magnaflow has a kit for Lightning but I don't have the mounts installed for it.

 

Good idea. you have the 5.4? If so, long tubes, high flow cats, x pipe, dual magnaflows, and your choice of exit.

 

Go with Dynatech's and x-pipe and maggies as Built54 said.

remove the cats if at all possible

 

I have the 4.6. I've been thinking about getting some turndowns and installing them right after the muffler. Which would be louder standing outside the truck, turndowns under it or 4"x18"s going out the back? I know the 4" x 18"s would be louder in the back but I'm thinking overall around the whole vehicle.

 

my turndowns are louder all around...

 

Thanks. I'll probably go with turndowns even though I like the looks of duals out the back. The 4.6s aren't very loud so anything helps.

Should I go with something like this for the bolts?

http://cgi.ebay.com/ebaymotors/STAGE...spagenameZWDVW

 

those are really good.