Wheelbase

[duster3404speed]

I seen somewhere that a roadrunner wheelbase was 116 and a superbee was 117. Where is the extra inch at? From w hr at I'm seeing in parts it's all the same with the understucter

 

[mopar 3 B]

Springs and front hangers

 

[dvw]

Many Dodge B bodys were longer than the Plymouth. The distance increase was in the rear passenger floor pan area.
Doug

 

[dsd1967]

I agree with Mopar 3 B, it's in the springs and hangers.

If you look at the AMD catalog, the floor pan, rear footwell, rear floor and rear trunk are the same part numbers for 68-70 dodge and Plymouth B body (except the trunk floor is different for charger due to the fuel fill). Same with framerails.