'1970' Road Runner '383' vs. AMC Rebel Machine '390'
The 1970 Road Runner 383,
335 HP ~ #3475 lbs. = {10.37 Wt/Hp}
Could be purchased with gears up to 3.91 though very few were ever ordered that way.
Most came with the standard {3.23 Sure-Grip}, and/or with 3.55 cogs.
Code #A31 {3.91 Gears} was the 'High-Performance Axle Package'.
If the 1970 Road Runner was 'optioned' with 3.91 Gears and the 'Air Grabber' air induction unit, a 4-Speed {with performance tune-up} was capable of 14.30's @ 98 MPH.
The 'California Emission' Holley Carburetor cars {Holley #4367} with {1 9/16" Primary ~ 1 3/4" Secondary} with a 680 CFM Rating actually were better performers on the track, if you 'yanked' all the C.A.P. pollution control vacuum lines off the Carb and Intake.