Installation Instructions, 65-66 Booster Template, 65-66 PB Firewall Template

The kit is designed to use a 1983-93 Fox-body Mustang 4-cylinder booster, an 80 Fairmont booster, or a MustangSteve-provided booster of the same design, so replacement boosters are always available using original Ford parts.

This conversion works with 1965-66 Mustangs with automatic transmissions, and also fits manual transmissions with cable or hydraulic clutches — it does not work with an original toploader transmission using the factory z-bar clutch linkage, since the clutch actuation rod interferes with the booster stud location; a T5 or TKX transmission with a cable-actuated clutch works fine.

The kit fits any combination of drum or disc brakes provided the correct master cylinder is used.

It can also fit Falcon and Ranchero with some extra welding to relocate the pedal pin; early Falcons (60-63) must use the original-style master cylinder or a Shelby-style export brace with a tandem master due to shock tower clearance.

Q: Is this a complete bolt-in booster kit?

No — this is the PB-2 conversion package: the redesigned brake pedal pin, firewall mounting bracket, hardware, and detailed installation plans that let a 65-66 firewall and pedal accept an aftermarket power booster. It's a DIY fabrication-level kit, not a bolt-in booster by itself.

Q: Do I need to buy a booster separately?

Yes. Pair this kit with our 65-66 9" power brake booster (sold separately) — PB-2 is what lets that booster mount to your car.

Q: Will I need to weld anything?

Yes — both the redesigned brake pedal pin and the firewall mounting bracket require welding. The pin is welded into the brake pedal arm, and the firewall bracket is tack-welded to your pedal support assembly, then fully welded once alignment is verified, per the included plans. This is best tackled by someone comfortable with metal fabrication and welding, or at a shop that specializes in this kind of work.

Q: Is there a template to help me position the booster mounting holes on my firewall?

Yes — use our free 65-66 Power Booster Firewall Template. Cut it out and tape it to the firewall from the engine side so the template's top two holes line up with the existing upper bolt holes, and the center hole aligns with the old master cylinder hole. You'll only need to drill the two new lower 1/2" holes and slightly enlarge the center hole — don't enlarge it more than necessary, since the booster bellows can't touch the edges of that hole or booster function will be impeded.