Several -- in fact -- MANY factors to consider crucial to proper braking - regardless of the power vs manual question. Consider this - how many RACE CARS have power brakes? Almost NONE.
There are several guys on this board that REALLLLLLLLY know about all this stuff... But I'll give you just SOME things to keep in mind. From there - it's up to you to educate yourself on what you need/want.
The key to all of this is to have the proper size of EVERYTHING in the system - because brakes are like the Cam and Head combo - one without the proper other - is a dog...
There's more to it than just the Master cylinder
... and the rule of thumb here is the larger the mc bore - the LESS pressure it will make... the smaller the bore - the More pressure they make. A 1 1/8" bore will make about HALF the pressure of a 7/8" bore.
Pedal ratio is critical
- 6 to 1 minimum on a MANUAL system. Most P/B systems use 4 to 1. Think about this -- 100 #s of "effort" on a 4 to 1 makes 400 #'s of effort -- vs the 6 to 1 ratio which makes 600 #'s... and DISC BRAKES are all about PRESSURE (there's a volume issue too - but now we're getting technical).
- Disc brakes use 3/16" lines -- Drums use 1/4". If you want to make pressure at the master cylinder - and have this pressure all the way to the actual brake - you need the smaller diameter lines... if you go DISC brakes - change the lines if you need to. Why waste all the money and effort on fancy brakes and MC's only to have it not work correctly. Think about headers - fancy cam - fancy heads - poopie little header size is the choke point. (okay - lets not go there with the small pipe torque argument - this is just a basic discussion...LOL)
Brake Bias/Proportioning valve
- You want the FRONTS to lock up BEFORE the rears... many factors here - tire size - brake size front vs rear etc... so not every system needs a proportioning valve... if you have huge rear tires and smaller fronts, the tires themselves might set your bias... but - big butt - It's one of those "better to have it, and not need it, than to need it, and not have it" parts. IMHO. The COMBO valves are for factory set up - engineered for a particular tire size and brake size and car weight etc - so an ADJUSTABLE version is what you need. It goes to the REAR brakes - in order to REDUCE the pressure to them - to get the fronts to lock BEFORE the rears. You lock the rears first - you spend a lot of time driving backwards.
Master cylinder BENCH BLEEDING
- Skip this part at your own peril. Many "skippers" try to do this after the cylinder is mounted on the car... or don't do it at all. They're dumb and lazy and deserve the hassle they just set themselves up for. There's lots of instructions available for this - but take my word for it - you leave some little itsy bitsy air bubble in the MC - IT WILL reduce the pressure you can make and it WILL poke it's ugly head up just before you hit that tree.
- Typically there should be a 10# residual valve (think "check valve") to the rears IF you're running DRUMS (in the rear)... This will "hold" the shoes "at the ready" and not let the wheel cylinder collapse all the way back... Different system
-- IF the MC is mounted LOWER than the brake system - you need to run a residual valve to both front and rears. In this case 2# valves for disc system... and the 10# for a drum system - you need these in BOTH lines -- one to the fronts and one to the rear depending on the size examples as given.
Do some research and some reading... don't rely on what your friends "think" you should do... this is too important. The manufacturers have good techs that will help you work towards a solution. Kore3 - Baer - Wilwood - Brembo... all good people that are interested in setting you up with a great braking system.