type of brake booster

[Steve83]

...a dual piston caliper master cylinder would simply be more powerful...?

No, the MC doesn't make any power. It moves fluid, and 2 pistons need more fluid than 1 to move the same distance. So using the single-piston MC on the wrong truck would take less foot effort, and the pedal would hit the firewall before the dual-piston caliper put enough braking force on the disk to stop the truck. Using the correct MC would require more foot effort, because it's moving more fluid with less pedal travel.

All that only applies to a truck with dual-piston calipers, so find out what yours has before going farther.

[Ford F834]

thank you for the replies everyone. So it sounds like a dual piston caliper master cylinder would simply be more powerful as it had to operate two calipers versus one? And so if the choice is up to me I would just assume having a more powerful master cylinder. Does that seem like a safe assessment ?

Okay, as Steve already pointed out, the reason for a different dual piston master is it has to move more fluid. It does this with a larger cylinder bore. If you put this on a single piston truck the pedal won’t move down as far when you brake. It will feel firmer sooner and stay up higher. It won’t brake any better or be any more powerful.

Also note that the light duty master cylinder that goes with the flat style booster has mounting bolts closer together than the one for the “deep” style HD booster. They won’t physically fit together. Also the brake line fittings for the light duty ones are different sizes. They won’t physically fit either.

Your best bet is to replace you parts with exactly what came on your truck. If you want better braking you need the pedal, the booster, the master cylinder and the steel brake lines to the pressure differential valve. In my opinion the only upgrade worth all that is hydroboost from a F450 in which case you also need the two pressure lines for the power steering fluid.