Hello,

I have talked quite a bit lately about choosing an exhaust for my 6.0 swap, and I think I am most set on a 3.5" or 4", since I plan to fab my own with a Hooker Maxflow muffler. The Y will be dual 2.5" for the 3.5" or dual 3" for the 4".

Can I fit a 3.5" exhaust without having to purchase a panhard relocation? I have no current plans to lower the car, especially since the roads are pretty bad here, so no need to adjust the suspension parts.

I've also brought up tire size. My plan is to make in the range of 380 to 420 RWHP. Which means stock size 245mm width tires are not wide enough. Hawks makes the 17x9 IROC wheels, and they can fit 275mm wide tires on them. Is that going to be wide enough for my power goals?

 

I have a 3.5" pipe over the axle with stock panhard brace and it clears. Not much room for error though. My particular pipe is the Hawks Motorsports version made for them by Stainless Works.

Regarding traction, I think the softness of the rubber is more important than whether you're a 245 or 275 tire. In general, the lower the tread wear number, the stickier the tire. 200 tread wear is about the limit of what can be reliably driven on the street three-seasons of the year. The deciding factor is probably going to be whether you can even find a tire you like in the 16". That's where changing to a different wheel size can open up more choices of tire rubber.

For reference, a drag radial is so soft that it has a 0 treadwear. Life is so short that it doesn't even register on the DOT scale of tire life.

 

I have no experience with a 3.5" exhaust (my car has a 3" pipe), but I'd say if you have any trouble, fab it.
Modify the panhard rod to allow the pipe. It's really not that big of a deal.

About the tires: 245s won't be enough, unless you baby it.
And what's the point of having a big-power V8 if you're going to drive it like it's got a 4-cylinder?
You need more traction, and like QwkTrip said, you're going to be really limited on GOOD tire options with 16" rims these days.

Fun fact: I changed the size of my daily AND my son's truck from 16" to 17" JUST because of better tire options (I get free used tires at work).

 

Thanks guys! I'm pretty close to ordering a few mandrel bends to start on building up my exhaust. I'm mostly going to loosely copy the over axle pipe from the hooker kit I have sitting around. I thought it was a few 90° bends, but I measured a 90°, an 80° and a 60° bend. After the muffler, I think the regular 90° followed by a 45° tucked up with a chrome tip on the end would look pretty nice.

I kind of guessed the 17 wheels might be a better overall choice. The 16 tires only go to about 340-ish tread wear. And then 17 tires go far lower.

 

Hi some years ago I installed a Mufflex 3.5" cat back Spintech muffler. fitment of the 3.5" tubing was great with the factory panhard location. The only issue I have with the system is that big Spintech muffler is a pain to keep in position, it tends to want to sit low on the passenger side. Since the car is under the knife for my 6.0 LS mod. I plan to address that problem. For tires like has been said you will probably have to lose the 16" wheel size for possibly an 18" wheel/tire combination. My 'Z' has been such a long project I severely miss my favorite ride but life issues get in the way. Good luck my friend.

 

Thank you for the information! I have heard that the Spintech mufflers sound really great! I do really like the Mufflex setups. However, I personally would rather have the dual tips and not the single tucked up single outlet. Mufflex does have an option like that, but it is very expensive. I am considering throwing my 3" Aerochamber setup on until I have the money to get a better exhaust. Especially when I have to buy different wheels and tires, which are probably more important than missing out on a bit of HP for the time being. I will be ordering my Speed Engineering LTs soon, and then I'll fab up a Y pipe. I guess the alternative is getting the Spintech with dual outlets and fabbing up the 3.5 in, 3.0 dual out myself. Thanks and good luck with your build, as well!

 

Mine has the dual outlet Spintech. Running without cats and the original TPI motor it sounded like an old Winston Cup car deep, throaty, and loud. I liked it. Some have said the Spintech doesn't flow as well as some other mufflers but as far back as it is I don't know if that is an issue. I'll see how it works with my 6.0 when I get it running.

 

I have a 4” but I did get an aftermarket upper PHR to make it work. There are pics in my build thread in my signature if you want to see the details.