Stainless Catted Headers Not Fitting? (2020 Mustang GT)

[In5am0us]

Is anyone having a problem with stainless power catted headers not fitting?
I bought a pair for my 2020 Mustang GT and the shop has tried moving the motor mounts and all and it still will not fit the passenger side. The driver side fit fine.

We sent the part to stainless and they claim it fits perfectly yet we havent been able to fit it.

Does anyone else have any experience with this and/or suggestions?

Sponsored

 

[LethalPerformance]

Is anyone having a problem with stainless power catted headers not fitting?
I bought a pair for my 2020 Mustang GT and the shop has tried moving the motor mounts and all and it still will not fit the passenger side. The driver side fit fine.

We sent the part to stainless and they claim it fits perfectly yet we havent been able to fit it.

Does anyone else have any experience with this and/or suggestions?

What exactly isn't fitting? Pics?

I haven't seen a single set of SW headers not fit. Are you sure the shop performing the work is capable of the install? Has experience installing headers on an S550?

 

[In5am0us]

What exactly isn't fitting? Pics?

I haven't seen a single set of SW headers not fit. Are you sure the shop performing the work is capable of the install? Has experience installing headers on an S550?

they said that the passenger side header is hitting the chassis.
is there something needed to be done to adjust and fit it?

 

[SheepDog]

I just installed a set of Stainless Power 1-7/8 headers on my MACH1. (on jackstands no less) and didn't have any issues with fitment. The tab holding the AC line does need to be unbolted and rotated upwards, and I went a bit further and used a metal ziptie to pull the AC line towards the fender a bit to keep it from tapping the header. Then, loosen the motor mount nuts (the top ones, not the mount to frame bolts) and use a long prybar to press between the aluminum motor mount and the body of the car to shift the motor over to the drivers side as much as possible.

The shop should have already had these nuts off the mounts, and the motor jacked up

 

[NGOT8R]

they said that the passenger side header is hitting the chassis.
is there something needed to be done to adjust and fit it?

Did you by chance purchase the ones with 2” primaries? If so, that could be the problem.

one solution would be to dimple the primary that’s making contact with the chassis in a vice. Heat the primary up until it’s red hot and then tighten the vice to make it look clean and professionally done.

 

[In5am0us]

Did you by chance purchase the ones with 2” primaries? If so, that could be the problem.

one solution would be to dimple the primary that’s making contact with the chassis in a vice. Heat the primary up until it’s red hot and then tighten the vice to make it look clean and professionally done.

i got the 1 7/8ths

 

[In5am0us]

I just installed a set of Stainless Power 1-7/8 headers on my MACH1. (on jackstands no less) and didn't have any issues with fitment. The tab holding the AC line does need to be unbolted and rotated upwards, and I went a bit further and used a metal ziptie to pull the AC line towards the fender a bit to keep it from tapping the header. Then, loosen the motor mount nuts (the top ones, not the mount to frame bolts) and use a long prybar to press between the aluminum motor mount and the body of the car to shift the motor over to the drivers side as much as possible.

The shop should have already had these nuts off the mounts, and the motor jacked up

they should have but ill mention this to them. the driver side fit perfectly which is weird

 

[SheepDog]

they should have but ill mention this to them. the driver side fit perfectly which is weird

Not weird. there is a ton more room on the drivers side. Your shop is doing something wrong I suspect....

The passenger side is very close with 1-7/8 primaries, but it does fit. I have maybe 1/2" clearance

 

[NGOT8R]

i got the 1 7/8ths

Oh okay. The same method of gaining clearance can be used on 1 7/8 too.

FYI, I read a thread where a shop beat and kinked a set of headers to see if it hindered performance. The test revealed that beating and smashing the header primaries did not result in a loss of power.

 

[In5am0us]

Not weird. there is a ton more room on the drivers side. Your shop is doing something wrong I suspect....

The passenger side is very close with 1-7/8 primaries, but it does fit. I have maybe 1/2" clearance

I also got the aftermarket connect. i have a borla atak. not the corsa, not mbrp so maybe the aftermarket connect is causing the problem

 

[In5am0us]

Oh okay. The same method of gaining clearance can be used on 1 7/8 too.

FYI, I read a thread where a shop beat and kinked a set of headers to see if it hindered performance. The test revealed that beating and smashing the header primaries did not result in a loss of power.

my shop guy mentioned this as a possible solution so im glad that smacking the headers wont cause any issues if its a last resort

 

[NGOT8R]

my shop guy mentioned this as a possible solution so im glad that smacking the headers wont cause any issues if its a last resort

Yes! Getting ample clearance will save you from lots of aggravation such as, chasing false knock, rubbing a hole in the header primary etc. This is how I would approach it if I were in your shoes.

Another thought is to ask your mechanic if lowering the engine via Steeda or BMR adjustable motor mounts will give you the clearance needed without having to massage the header primary tube.

 

[In5am0us]

Yes! Getting ample clearance will save you from lots of aggravation such as, chasing false knock, rubbing a hole in the header primary etc. This is how I would approach it if I were in your shoes.

Another thought is to ask your mechanic if lowering the engine via Steeda or BMR adjustable motor mounts will give you the clearance needed without having to massage the header primary tube.

good to know. thanks for this!

 

[NGOT8R]

good to know. thanks for this!

I used the Steeda adj. motor mounts on mine with my headers to lower the engine 1/4”. Different brand of headers, but I have plenty of clearance on the passenger side between the primary tube and frame.

 

[In5am0us]

I used the Steeda adj. motor mounts on mine with my headers to lower the engine 1/4”. Different brand of headers, but I have plenty of clearance on the passenger side between the primary tube and frame.

I’ll show my shop guy these pics for sure

Sponsored