Doug Thorley Headers

[Spike Morelli]

I've been checking out the various header manufacturers offerings for my '71 Mach 1 with a 351c, and have decided on Doug Thorley headers, they have thicker flanges ( 3/8ths in ) and heavy tube walls ( 14 Guage). However, from what many guys have posted, most people are using Hookers, Hedmans, lots of specialty manufactures, but I don't recall anyone posting they have the Doug Thorley made pieces. If you're running them, I'd like to hear from you about your thoughts on them, although I'm fairly set on buying from them, others input is always helpful as to how they fit, ground clearance, etc.

 

[mach71351c]

I had a 88 F250 with a 460. I installed a set of thorley headers after cracking to sets of manifolds. Never had any leaks and they fit very well.

As for your Mach 1,I would check out ford powertrain application headers. I installed a set on my brothers Boss 302 they fit perfect. The quality is 2nd to none. I bought a set for my Mach 1 and can't wait to install them.

The 1st pic are the Boss headers and 2nd is Mach headers.

 

[c9zx]

I had a 88 F250 with a 460. I installed a set of thorley headers after cracking to sets of manifolds. Never had any leaks and they fit very well.

As for your Mach 1,I would check out ford powertrain application headers. I installed a set on my brothers Boss 302 they fit perfect. The quality is 2nd to none. I bought a set for my Mach 1 and can't wait to install them.

The 1st pic are the Boss headers and 2nd is Mach headers.

The second set looks like they have a better collector design. I've been considering the FPAs for my Boss 302 but the collector design really slow me down. Chuck

 

[Spike Morelli]

Some years ago, I swapped out my tired 2V engine, for a hot, hopped up 351c 4V four bolt mains with all the bells and whistles, ( Edelbrock, Holley, MSD , Engle cam, etc ). Within the first week, I crushed the headers on a speed bump at the grocery store parking lot, ( the headers were a swap meet buy). Eventually I rebuilt the stock 2v and put her back in. I always assumed that the reason I crushed my headers back then, was that they were bought at a swap meet, and I probably had been sold the wrong application tubes for my car, but, I see lots of guys with '71-'73 Mustangs experiencing the same thing. My Mach is not lowered, sits on new springs all around, on 14" original wheels. Headers are, on most cars, an easy, bolt on upgrade. I guess it's just the nature of the '71-'73 design that ground clearance is an issue. For every day driving useage, as I do, bashing the headers on speed bumps and driveways makes the conversion a heartache. I know better.....yet here I am...considering a header system, again....

 

[eddyw]

I buy them new in the box from Summitracing and sold the Doug Thorley Headers.

Very, very nice material and quality but they fit not on mine Mach 1-1973, the driver side hit the steering box.

Maybe they fit a '71/'72 better???

See also this thread:

http://www.7173mustangs.com/thread-emergency-question-about-exhaust?highlight=Doug+Thorley+headers

https://www.summitracing.com/int/parts/dte-265-2v-c/applications/year/1973/make/ford/model/mustang?prefilter=1

 

[4Vforever]

I had a 88 F250 with a 460. I installed a set of thorley headers after cracking to sets of manifolds. Never had any leaks and they fit very well.

As for your Mach 1,I would check out ford powertrain application headers. I installed a set on my brothers Boss 302 they fit perfect. The quality is 2nd to none. I bought a set for my Mach 1 and can't wait to install them.

The 1st pic are the Boss headers and 2nd is Mach headers.

The second set looks like they have a better collector design. I've been considering the FPAs for my Boss 302 but the collector design really slow me down. Chuck

Totally agree with that on the design of these headers. They have next to no collector for clearance reasons. There's a reason why things like pipemax calculate things like collector length and diameter for a reason. I've personally seen incorrect exhaust design cost nearly 50HP, but have heard first hand and read of around 100HP being gained. They are a nice looking headers, but not what you'd want for maximum performance. Nothing wrong with them on a nice decent streeter though and not everybody is looking for every bit of power they can get.