719 Posts . Discussion Starter • #1 • May 12, 2005. A brake booster is designed to provide power-added assistance to help apply the brakes. 1,050 Posts . My hope is that with the improvement in pedal leverage, (But without any power assist) the same bore size master cylinder should provide similar brake force with similar effort as now. Most brake pedals have both upper and lower holes for brake master cylinder attachment. Should a 4 wheel manual brake car stop as well as a power brake car? That would tell me that power drum brakes had the same pedal as non-power drum brakes for the same transmission choice. The 1975 Ford parts manual lists 4 Mustang brake pedals for 65/66. It’s mainly due to the job of a brake booster that a vacuum-assisted system is called a power brake booster. Some of the guys have recommended ditching the booster and just changing to a smaller bore master cylinder. The manual/non power master cylinder I have to use is an aluminum 15/16" from Dr Diff. Just make sure you have a manual brake m/cyl. Getting ready to install my cpp brake conversion kit on my 63 nova. If you have questions regarding disc brake master cylinders and drum brake master cylinders, we may have answers for you. Disc and drum both have their different pedals for manual vs. automatic transmission. The real differentiating point between power and manual brakes is whether or not the master cylinder has a power brake booster attached. It’s also common for a hydraulic-powered brake booster to also be associated with the term power brake booster. All the brake hardware at the wheels will be the same, power or manual. Some late 70's and 80's cars utilize a pressed in pin from the factory for either manual brakes (upper hole) or power brakes (lower hole) and a open hole for the other. You need to have the correct M/C for manual brakes. Discussion Starter • #1 • Apr 29, 2013. A correctly setup manual brake system will lock up the brakes no problem. I'm slowly rebuilding my 70 mach 1 and I'm contemplating using a non-power Wilwood master cylinder instead of the vacuum assisted one that came off. Without the power booster, the firewall really gets cleaned up.Plus there's a lot more room to get at everything on the driver's side, like that back spark plug. Power Vs Manual Brakes (4 wheel disc conv) I am looking at the Wilwood kit and the Touring Classic C5 Brake kit to convert to 4 wheel disc brakes. There is a little more pedal throw before the brakes … Discussion Starter • #1 • Aug 2, 2010. just going from a 15/16" bore like i used in the manual brake setup in my Nova to a 1 1/4" bore like i would have used had i been running power brakes represents a HUGE increase in the amount of fluid that gets pushed thru the lines for a given amount of master cylinder stroke, which translates into a much harder pedal without the boost. :agree: 68 L-71 with manual brakes and as Gary says it hauls down just fine. The upper hole is for manual brakes, and the lower hole is for power brakes. No vaccuum issue, no booster in the way. Simply put, a power booster helps assist the master cylinder piston apply force when you press the brake pedal. As for the performance, the brakes feel fine after I bled the brakes. We just switched from PB to manual on a 450hp vette. 8 Posts . There is no mention of power brakes.