My Cuda in full "Street" trim, goes 9.89 at 134mph....I run Hooker headers 2.25 tubes to 3.5" collectors shrunk down to 3" exhaust and 3" flow masters....No x pipe....

60ft is a 1.33 so far....on DOT "tires"...

Take the mufflers and exhaust off and open it to 3.5" wide open....Same ET.

'70 Cuda,...605 EFI Hemi Street Car (6.20 best pass, 1.33 60ft)
https://www.youtube.com/watch?v=WYw6RA-k5Bk (6.25 at 108.75mph from inside car)
https://www.youtube.com/watch?v=3zQEb9uxFng (6.25 at 108mph from outside car)
https://www.youtube.com/watch?v=JCvfzsC4NgM (9.9)

'66 Barracuda AWB Stretched nose Blown 440 Car in build stage

'71 Duster Drag Car 400 Low Deck 512 best 6.002 at 115.44mph
https://www.youtube.com/watch?v=Znuo3jMUXTk