At the beginning of chase combat every vehicle make a manoeuvre roll (2d6 + vehicle Move + drive skill) trying to get better position. Loser gets a +1 bonus for the next manoeuvre rolls and it is cumulative until he wins. You can represent that +1 as tokens or coins for easy reference.
The winner picks one of the options below:
ATTACK Player rolls 2d6 + vehicle Combat + gunner bonus. If the result is equal or higher than target’s DEF, the attack hits. Roll weapon damage and apply it to target’s HP.
CLOSE Player move close to target vehicle. If he wins manoeuvre roll next turn he can RAM the target vehicle or attack using PERSONAL WEAPON to occupant.
DISENGAGED Player disengaged from chasing. If he wins manoeuvre rolls next turn he can ESCAPE.
ESCAPE Player escape from the chase.
RAM Player rams target vehicle! Roll vehicle ram damage and apply it to target vehicle’s HP. If he wins manoeuvre rolls next turn, he can RAM once more.
PERSONAL WEAPON Make an attack roll. Victim must be in target vehicle car and he received DEF bonus of the vehicle he is in when attacked.
When the winner had taken his turn, all vehicle make manoeuvre roll once again. Repeat until one side loses.
Here are some vehicle stats for everyone to play. I stat Mad Max Fury War Rig and Nux Buggy
DEF 9, HP 65, Combat 1, Move 2, Ram 6d6, Shield 10, DEF Bonus +3,
Personal Weapon: Guns (1d6), Shotgun (2d6), Flaregun (1d6, target stunt)
Physical 4, Mental 2, Combat 4, Social 1, HP 25, DEF 7
Skill: Drive (2) +3 to when manoeuvring vehicle.
Physical 2, Mental 3, Combat 3, Social 2, HP 18, DEF 7
Skill: Drivev(2), Sharpeyes +2 when shooting.
Nux BuggyDEF 8, HP 20, Combat 1, Move 3, Ram 3d6, Shield 3, DEF Bonus +2,
Weapon: Thunderstick x 6 (3d6)
Mod: Nitrobooster (roll 3d6 and pick 2 of the best when manoeuvring)
Physical 1, Mental 3, Combat 1, Social 1, HP 12, DEF 7
Skill: Drive (1) +2 when manoeuvring vehicle.
Physical 1, Mental 2, Combat 1, Social 1, HP 12, DEF 7