MSD Pro-Billet locked-out distributors are built from strong billet aluminum for engines that run locked-out timing or an MSD timing computer. This extra support ensures stable and accurate timing signals throughout your engine's entire rpm range. ...

What is the advantage of locking out a distributor?

If you drive on the street, a PROPERLY curved distributor will have better driveability, gas mileage, low end torque, and throttle response over one that's locked at "one number" ANY day of the week.

What does it mean when a distributor is locked out?

locked out. or. locked in.. it means that the distributor internal advance mechanism does not change / move the timing... some electronic ignition systems can have a "internal" electrical or electronic mannor that changes (retards) the timing....