On Sunday afternoon, NHRA's Technical Department issued the following clarification on headers.

Double-pipe insulated exhaust headers mandatory. Minimum Funny Car header angle 40 degrees, measured in reference to ground and parallel to
the center line of the car (X axis). Maximum width of headers: 83 inches. Maximum header height 11.5 inches, measured from the ground to the
highest point at the exit of the exhaust. Maximum header pipe O.D. 2.75 inches. O.D. and I.D. must remain constant beginning 8 inches below the
header flange to the exit of the header. Centerlines of all four exhaust pipes must be parallel to each other and each pipe must contact adjacent tube. 
 
NHRA confirmed this rule will be enforced beginning at the Dodge Mile High Nationals outside of Denver, Co.

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