Originally Posted by Medlock51
One plug fires 20 degrees btdc...the second fires 5 degrees atdc to clean up the nox emissions.

This is incorrect. They fire at the same time.

1975 Jeep Cherokee compound turbo 5.7 Hemi/6 speed AutoX/Drag/Street.
9.97 @ 140 slicks, 10.74 in autox trim