Mach 1 Change in late 03 and 04 Mach 1 heads ?

[CanuckMustang]

I'm considering buying a late build date 03 Mach 1. Is there any truth that Ford improved the heads (i.e. grinded exhaust ports) late in the model year to improve performance? Supposedly the better heads have blue markings on them and flow noticeably better (as per a thread on Mach-1org web site).

I'd also like to know if the new exhaust systems on 04 models increased horsepower.

Anyone out there know the facts or have seen dynos that prove this?

I'd appreciate any help as I am looking to buy a new 03 or 04 Mach 1 right now.

 

[Snakeeper]

I'm considering buying a late build date 03 Mach 1. Is there any truth that Ford improved the heads (i.e. grinded exhaust ports) late in the model year to improve performance? Supposedly the better heads have blue markings on them and flow noticeably better (as per a thread on Mach-1org web site).

I'd also like to know if the new exhaust systems on 04 models increased horsepower.

Anyone out there know the facts or have seen dynos that prove this?

I'd appreciate any help as I am looking to buy a new 03 or 04 Mach 1 right now.

Nope! They are the same heads. I have an 03 and it has dynoed at 295rwhp and 308 torque SAE!

 

[lamach1]

I'm considering buying a late build date 03 Mach 1. Is there any truth that Ford improved the heads (i.e. grinded exhaust ports) late in the model year to improve performance? Supposedly the better heads have blue markings on them and flow noticeably better (as per a thread on Mach-1org web site).

I'd also like to know if the new exhaust systems on 04 models increased horsepower.

Anyone out there know the facts or have seen dynos that prove this?

I'd appreciate any help as I am looking to buy a new 03 or 04 Mach 1 right now.

As far as I can tell, there is no difference. Early cars have dynoed as high as later cars. As far as the blue paint on the heads, it has been verified that some of the cars with the early build dates also have the blue paint.

 

[CanuckMustang]

There must be a difference in the 04 Mach 1 power ratings. The highway fuel consumption is down 1 mpg on the 04 vs 03's indicating an improvement in efficiency. On the contrary the highway consumption is up 1 mpg on the 04 GT suggesting a loss of power.

 

[TR03Mach1]

You'd be hard pressed to prove to me that there is a difference. I have a very early build 03 Mach 1 (Nov 8, 2002) and my engine has blue paint on the driver's side head, but not on the passenger side. I understand that the 04's have a six-brick cat system vs the 03's four-brick cats. I just had mine dyno'd and it's putting out more power than a lot of 04's. See sig.

 

[760-MPH]

Nope! They are the same heads. I have an 03 and it has dynoed at 295rwhp and 308 torque SAE!

can i see your dyno please?