Finding headers to swap a 351W into a Mustang is a challenge
Below are headers I have found. The Powertrain headers are you best choice for fit and power but only fit 1967-1973.

The Hedman hedders are not intended for the 1/8" raised exhaust ports of the AFR 205 heads.
The shortie headers either Hedman or JBA should work, but headers often prove to be a challenge to fit.

 

 Powertrain Custom Headers

1967-73 Mustang 351W with Dart / Canfield / AFR205 Heads (full 1 3/4" tube to fit large port heads)

$540 Uncoated
$600 Chrome coated
$740 Ceramic coated

Will clear Lakewood Bell housings
Will fit Total Control Rack & Pinion Steering
Manual & power steer applications
1 3/4" Primary on Dart Head- 1 5/8"/ 1 3/4" Step option for stock port heads
 

 Upgraded to Ball and Scoket fit for better sealing see 302 header below.

 

 

 1965-73 289-302-347 W/ GTP & Dart Heads

 

Year	Model	Engine	Design	Notes
55-57	T-Bird  New	Y-Block 292-312	4 Tube Step
58-60	T-Bird	F.E.	Shorty	A    B    C    E
61-66	T-Bird	F.E	Shorty	C
67	T-Bird New	F.E	Shorty	A  B  C
55-59	Ford Passenger	F.E.	Shorty	A     B    C     E
55-59	Ford Passenger	429-460	Shorty	C    D    E    G
60-64	Galaxie/ Mercury	F.E.	Tri-Y	A    B   C    E   H
60-64	Galaxie	429-460	Shorty	C    D
65-70	Galaxie	F.E.352-428	Shorty	A    B    C    E
60-70	Galaxie	F.E. 352-428	Shorty
65-73	Mustang/ Cougar	289-302 W/ GTP & Dart Heads	Tri-Y	C    G    H    K
65-66	Mustang	351C 2V/4V	4 Tube	G    *    H
65-73	Mustang	302C High Port	4 Tube	*
66-73	Mustang/ Cougar	351C 2V/4V	4 Tube	E    G    H
67-73	Mustang/Cougar	351W/Dart/Canfield/AFR205 (full 1 3/4" tube)	4 Tube	C    E   K   L
67-73	Mustang/Cougar	351W w/standard Ford Port (step design 1 5/8 - 1 3/4)	4 Tube Step	C    E   K   L
69-70	Mustang/Cougar	Boss 302	4 Tube	C    E
65-70	Mustang/Cougar	Boss 302 2V/4V	4 Tube	C    E
72-74	Torino/ Montego	351C 2V/4V	4 Tube	C
66-69	Fairlane/ Falcon	289-302 W/ GTP & Dart Heads	Tri-Y	C    G    H    K
66-69	Fairlane/Torino	351W/Dart/Canfield/AFR205 (full 1 3/4" tube)	4 Tube	C   E    K   L
66-69	Fairlane/Torino	351W w/standard Ford Port (step design 1 5/8 - 1 3/4)	4 Tube Step	C    E   K   L
66-70	Fairlane/ Ranchero	390-428	Tri-Y	A    B    C    E    H    K
66-67	Fairlane  New	429-460	Shorty	D
67-70	Mustang/ Cougar	390-428	Tri-Y	A    B    C    E    H    K
67-73	Mustang/ Cougar Revised 10/13-02	429-460	Shorty	D    G
79-93	Mustang	351w	Tri-Y	*
53-56	F-Series P.U.	429-460	Shorty	D    E    G
65-76	F100- F250 2WD & 4x4	352-428	Tri-Y	A    B    C    J
78-79	Bronco	429-460	Tri-Y	D    F    J

 

Notes:
A- F.E. Series include 352-360-390-406-410-427-428
B- F.E. Available in 16 bolt C.J./ 14 bolt GT/ 8 bolt Std. flanges
C- Manual & power steer applications
D- Available in 429 C.J. flange
E- Will clear Lakewood Bell housings
F- Automatic Trans only
G- Engine swap header may require slight modifications
H- Some 4 speed clutch linkage modifications possible
J- Available in ultra H.D. 3/8 flange 14 gauge tubing
K- Will fit Total Control Rack & Pinion Steering
L- 1 3/4" Primary on Dart Head- 1 5/8"/ 1 3/4" Step option

*- Call for application
 

  All F.P.A. headers utilize 2 1/2" or 3" ball and socket collectors

Most Std. production F.P.A. headers feature 3/8" one piece flanges and 16 gauge
tubing. Standard finish is nickel chrome. All headers are of the "inside the
frame design" and are completely welded with no slip joints. All F.P.A. design
headers feature maximum ground clearance and are shipped with gaskets, bolts
and street reducers. Performance coatings ceramic finish is available at
additional cost.   
 

 

 

 88650 $150

Header Material:	Steel
Header Finish:	Painted
Header Style:	Shorty
Primary Tube Diameter (in):	1 5/8
Collector Diameter (in):	3
Equal Length:	No
Primary Tube Gauge:	16-gauge
Collector Attachment:	Ball and socket flange
Cylinder Head Port Shape:	Oval
Flange Style:	Standard
Flange Thickness (in):	1/4
Bolts/Studs Included:	Yes
Gaskets Included:	Yes
Reducers Included:	Yes
Y-Pipe Included:	No
Quantity:	Sold as a pair.

Model	MUSTANG
Beginning Year	1964
Ending Year	1973
Engine Type	V8
Engine Size	5.8L/351
Engine Family	Ford small block Windsor
Engine Swap	No
Drivetrain	RWD
Power Steering	Yes
Power Brakes	Yes
Air Conditioning	Yes
Standard Transmission Column Shift	No
Standard Transmission Floor Shift	Yes
Automatic Transmission Column Shift	No
Automatic Transmission Floor Shift	Yes
Application Footnotes:	C - For 1964-74 vehicles without A.I.R. systems, are considered as O.E.M. replacement parts when existing emission controls are not removed from vehicle. 129 - Modification to shift linkage may be required. 214 - Elite replacement gasket HED-27340. 1 - Without smog injection or injection heads. 15 - Shortie-style header. Maximum ground clearance.

 

 88660 $155

Header Material:	Steel
Header Finish:	Painted
Header Style:	Full length
Primary Tube Diameter (in):	1 5/8
Collector Diameter (in):	3
Equal Length:	No
Primary Tube Gauge:	16-gauge
Collector Attachment:	Ball and socket flange
Cylinder Head Port Shape:	Oval
Flange Style:	Standard
Flange Thickness (in):	1/4
Bolts/Studs Included:	Yes
Gaskets Included:	Yes
Reducers Included:	Yes
Y-Pipe Included:	No
Quantity:	Sold as a pair.

Model	MUSTANG
Beginning Year	1964
Ending Year	1973
Engine Type	V8
Engine Size	5.8L/351
Engine Family	Ford small block Windsor
Engine Swap	No
Drivetrain	RWD
Power Steering	Yes
Power Brakes	Yes
Air Conditioning	Yes
Standard Transmission Column Shift	No
Standard Transmission Floor Shift	No
Automatic Transmission Column Shift	No
Automatic Transmission Floor Shift	Yes
Application Footnotes:	C - For 1964-74 vehicles without A.I.R. systems, are considered as O.E.M. replacement parts when existing emission controls are not removed from vehicle. 51 - Under-chassis exit. 157 - When equipped with manual transmission, will not fit with Ford top loader transmissions. 214 - Elite replacement gasket HED-27340. 1 - Without smog injection or injection heads. 27 - Power steering bracket HED-20120 required.

 

  88308 $285

Tork-Step Stepped Hedders, Exhaust Header, Tube Size 1.5 - 1.625", Collector Size 3", Without Smog Injection Or Injection Heads, Painted, With Automatic C-4 Transmission Only, Without A.I.R Systems Emission Controls Are Not Removed Considered OEM Repl.

 1970-71 Mustang 5.8L, V8, 2 Barrel, Windsor Engine - With Factory Air Conditioning, Power Steering, Automatic Transmission

 

 

 

 www.ajusa.com/cgi-bin/jba/lookup?ajr_skey=de5e79e689ceceb747ac76a15ebd3feb&part_num=1653

1653 Chrome Shortie 1965-73 Mustang 351W $600

These Headers are designed to scavenge the exhaust gas and reduce the restriction typical of the stock cast iron exhaust manifolds. By using the patented Firecone® collector JBA is able to create lots of horsepower and torque. Thick 3/8 inch Header Flange Comes With All New Hardware And Gaskets Includes Any And All Required Emissions Fittings Fits Nicely Within The Engine Compartment Limited Lifetime Warranty

HP & Torque: 15-20 HP/26 ft lbs Torque Installation: Direct replacement of the stock exhaust manifolds, header bolts up to the existing stock Y-Pipe/Crossover pipe. Requires minimum cutting and welding. Takes between 3 And 6 hours depending on application. Only simple hand tools required All hardware, gaskets, and instructions included. Tech Notes: Use 1970 motor mounts (D0Oz-6038-G or Sealed Power 270-2286) and 1966-1970 Frame bracket. 50 States Smog Legal!

 

 

Hedman Heeders for 1964-1973351W Mustang

88660

Header Style:	Full-length
Header Material:	Steel
Header Finish:	Painted
Primary Tube Diameter (in):	1 5/8 in.
Collector Attachment:	Ball and socket flange
Collector Diameter:	3.000 in.
Tuned:	No
Primary Tube Gauge:	18-gauge
Cylinder Head Port Shape:	Oval
Flange Style:	Standard
Flange Thickness (in):	1/4 in.