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OEM 426
Indy Cyl. Head
Keith Black
Alan Johnson
Brad Anderson
(Top Fuel)
Walt Austin Racing
(Top Fuel)
Stage V
Billet High Port
Viper Gen I & Gen II
Viper Gen III
Mitsubisi 6G72 3.0L V6
OEM 331 / 354 / 392
Alan Johnson 392
(Nostalgia Top Fuel)
OEM 383/413/426/440
OEM 273-360
Brodix B1-Spec
Mopar Parts W8
(Drag Race)
Mopar Parts W8 & W9
Mopar Parts P7
Mopar Parts P5
(Pro Stock Truck)
Brodix B1-BA
Mopar Parts W2
OEM 5.7L - 6.1L
Mopar Part 392

Now Available
SAP counterbored
Round counterbored Oversized
SAP counterbored Oversized
Normally we recommend slipping the primary tube through the flange and weld it to the head side of the flange allowing the thickness of the flange to reduce the sheer load on the weld. On some applications counterboring is only the way to utillize an oversize tube with the available sealing surface on the head. The flanges are machined .150" deep to support the tube and allow the tube to be welded to the inside of the flange.
Many aftermarket heads are advertised as Raised Exhaust Ports. In most cases the ports and bolt pattern are shifted higher together. We refer to a design as "Raised Port " when it is revised with the exhaust ports shifted higher on the bolt pattern (as shown in the illustration above.
Mitsubishi 4G63
SPD Precision CNC Machined Flanges are available 3/8 or 1/2 inch thick in 1018 cold rolled steel or 304 stainless steel.
(Other thicknesses and materials can be special ordered).
Use the application buttons on the left to find the correct bolt pattern for your heads. Then use the associated link download the PDF with all of the flanges available with that specific bolt pattern.

In an effort to keep up with cyl. head manufacturers and CNC porting services, we are continually adding new appication to our line of flanges. If you don't find what your looking for give us a call or send us a rubbing.