GT350 valence with custom exhaust plan

Got my Summit order in with clamps and the piping.

Valence wont be here until Tuesday though to test fit the fit; then will install next likely Friday.


I think I underestimated the distance between the 2 tips of the Y pipes bought as there were no specs. The tips are only about 3 3/4" between centers and 1 1/4" between the closest walls; probably way too narrow looking at pics of the borla setup.

It looks like from the screenshot below if the exists are 2.5" that the distance between is 2.5" or 3"

If someone knows the distance between the tips on the Borla setup that'd help.

Blk2015GT said:

Got my Summit order in with clamps and the piping.

Valence wont be here until Tuesday though to test fit the fit; then will install next likely Friday.


I think I underestimated the distance between the 2 tips of the Y pipes bought as there were no specs. The tips are only about 3 3/4" between centers and 1 1/4" between the closest walls; probably way too narrow looking at pics of the borla setup.

It looks like from the screenshot below if the exists are 2.5" that the distance between is 2.5" or 3"

If someone knows the distance between the tips on the Borla setup that'd help.

Click to expand...

I just finished a factory GT350 mufflers retro-fit with the active exhaust valves.

I measured the distances for you based on my dual exits which should be the same as the Y pipes leaving the FRPP gt350 mufflers since they use the exact same valance.

Center to center distance= 3.75"
Outside edges between each pipe= 1.25"

These measurements are not 100% accurate as I measured them while being mounted on my car and since the muffler exits are recessed in to the faux gt350 tips, an exact measurement is quite difficult. Hope this is what you're looking for.

-Nick

Very interesting, the Y pipe I linked to is exactly that; 3.75" centers and 1.25" inner edge to inner edge.

Looked way too narrow comparing to the photos, but don't have the valence yet. This may actually work.

Thanks!!!!

Tag. Very interested in the outcome of this.

subbed, really want to see how this turns out!

Valence should be here tomm. Will test fit the Y pipe to first see what needs to be adjusted to meet the valence tips; if anything. From the measurements above it should be close (hopefully)

Then Friday will be the test, install the valence on the car and see if the Y pipes fit between the mufflers and valence. Have to wait until a day off in case I need the exhaust shop (dont want to melt the valence driving around for days with single tips in the middle of the cutout)

Got the valence, the Y's I linked to were definitely too narrow.

The true measurements of the valence are 8.5" far edge of tip to far edge of tip. Each tip is 3" diameter inside. From inside one to inside the other (between the built i tips from inside edge to inside edge) is just at 1.25-1.5"

Thus a roughly 4.25-4.5" center to center between the pipes (1.5+1.5+1.5) to get the tips centered. 4.5 would be safer. I made these 4.5", 2" between the pipes and then 1.25 and 1.25 to find center.

I would suggest starting with Dynomax 88031 first; they have a 4.25" center between the 2 pipes; so would only require minor adjustment.

These AP one's were 3.75" centers so I had to spread them by 3/4" Luckily the spare tire jack makes a damn good pipe spreader. You can see the lines from the pressure of the jack edges slightly in the right leg of the right but who cares it's all inside the valence. I just have to tap the inlets back into round now with a hammer from stretching along the weld joint above them.

Really it sounds harder than it is, took all of 30 min or just get the Dynomax ones which start wider, which I should've done but were double the cost of these at $50 each one. I was not impressed with how these came, the pipe size it not uniform and one leg was bending in toward the other; not what was photoed with each leg being straight up and down, kind of like they are now. The welds, who cares all inside the valence.

I did hold them up to the mufflers with the valence up against the stock and it seems it will fit depth wise just fine. It looks like the cuts will be at or before those little bumps in the pipe inside the Y so they wont matter (not the you would see them anyway). So there is plenty of room with Roush axlebacks at least between the muffler and valence to clamp it.

Let's see it done!

So much want.

The valence is on the car, got anxious and just did it, but the Y pipes were fail. The inlets would not go back to round they are stretched too far making the inlet oval.

Got the valence on without taking the bumper off too, so all of 1.5 hours total off and new on.

Luckily my exhaust guy is going to fab some good fitting Y tips tomm morning for about $100.

All in all $825 ($50 on those wasted Ys too but oh well) isnt terrible for a GT350 setup. Versus the $1800 axleback setup its a $1,000 savings.

It's a much tighter fit than I thought though from the muffler outlet to the fake tips. Much tighter space than it looked initially so it may not have worked to begin with. Honestly let your local exhaust guy do it for $100-150. Plus the $725 valence you are not too deep in compared to the Ford Racing ludicrous pricing and have something that will fit well. Once you buy the pieces and tools its nearly as much as custom tips.

Sure I could go rent a pipe expander from autozone and fix the out of round but it's coming a huge project without the right tools or time to get it done

Perfect. So what I'm considering is getting the valance and installing then leaving the Roush axle backs with the single tip until I'm able to get to an exhaust shop

Synyster06Gates said:

Perfect. So what I'm considering is getting the valance and installing then leaving the Roush axle backs with the single tip until I'm able to get to an exhaust shop

Click to expand...

You have to remove the tips in order for the GT350 valance to go on.

kingstang said:

You have to remove the tips in order for the GT350 valance to go on.

Click to expand...

Correct. I suppose I should have worded it "single exit" rather than single tip. No one will notice unless they really get under there and look anyway.

I removed the mufflers being 1 whole bolt. The muffler exist is right between the fake tips, and while they're metal there is plastic around there. Dont want to damage a $750 part. And I have no idea how heat resistant that metal is or isnt to a direct blast like that.

Lay on your back under the rear and remove the midpipe clamp when the valence is already off. Plenty of room to work (even with the stock valence plenty of room to reach the bolt). that was MUCH easier than unbolting the fake tips to leave a gap there. 2 bolts are very easy to get to just on the underside of the valence but the 2 inside are a beast as they are way up in there.

No big deal to drive the shop with no mufflers, some run that setup full time.

How much room is there between the "business end" of the Roush mufflers, and the GT350 valence?

I have a similar setup (H-pipe, Roush Axleback), and I'm looking into doing what you're doing.

Make sure to upload some pics!

Maybe all of 1.5-2 inches because the fake metal tips jut back from the valence toward the muffler.

It is MUCH tighter than expected. This photo is looking in through the back of one of the valence tips; the right tip with center to the left..

There's a reason the Ford Racing ones have the Y start right off of the exit; the tolerances are so damn tight.

I dont see any way to make a slip fit clamp on solution with such little space between the end of the muffler outlet and the center metal of the tips; absent cutting that muffler outlet down a bit (it's a good 2" past where the hanger is welded on there) and welding on a Y.

There just isnt an extra inch or so to leave for the slip joint to get a clamp around and the U/Y part not be touching the metal fake tips in the valence (which will cause rattle). Maybe though, will see what my exhaust guy thinks this morning.