Q: Can I bolt this booster straight onto my stock 65-66 pedal and firewall?

No. This 9" booster is not a stock replacement for 65-66 Mustangs — it requires our PB-2 power brake conversion kit (redesigned pedal pin, firewall bracket, and installation plans) to mount correctly. Order the PB-2 kit along with this booster if that bracket work isn't already done.

Q: Single or dual diaphragm, and how much vacuum does it need?

It's a 9" single-diaphragm vacuum booster, which is proven sufficient for a 65-66 power brake conversion. It needs at least 18" Hg of vacuum at idle to work properly, so a stock-ish cam with a solid vacuum signal is recommended.

Q: What's the warranty?

1 year.

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.