Master cylinder recommendations?

[stinger]

I have 70 disc set up front,70 rear drum,adj. p valve and dist block with a 11/8" bore master.I dont care for how much foot it takes to stop the car.I dont think I could lock the brakes up if I used both feet,not good with a stout 440. Looking to try a 1' bore mc but gets confusing looking for the right one.
Help!

[stinger]

forgot to mention I'm running manual disc and hope to keep it that way.

[Katfish]

I'd go with the 85 Diplomat, but you'll need to get the 4 bolt to 2 adapter.
What calipers do you have?  The later A-body calipers can be used and have larger contact area.

[stinger]

the whole set up is from a 70 e body,single piston slider's. I had that adapter but since I recently moved it's gone M.I.A. my car was a manual drum car,bought the parts years ago before the nifty conversion kits came out,go figure. trying to keep it simple for now since the move it's been crazy.

[1970 RT Challenger 1970]

http://www.theramman.com/

The Ram Man will get you on track.

[bc3j]

I also have a '70 Challenger R/T that was a manual all drum brake car. I used this master with a 1" bore from Master Power Brakes. http://www.mpbrakes.com/products/product-detail.cfm?product_id=524
I have '79 Diplomat 279mm rotors with slider calipers that are 2.75" in diameter and have 11x2.5" rear drums with 13/16" wheel cylinders. My brakes are also manual and I just used the standard distribution block from drum brakes. Can't lock the rears from 55 mph stops. Car stops nice. The brake pedal has some movement to it but becomes rock hard less than halfway down. I like that feel.

[stinger]

thanks for the help everyone.keep 'em coming,got 3 weeks before the cruise season starts and I want to be ready.I've spent the last 15 years putting this car together.

[bc3j]

Great to hear. It's a good feeling to have it all together. Just got my semi-metallic front pads & they work great.

[stinger]

What about the A body MC? seems to be what I'm looking for.

[bc3j]

The only master cyl I've tried was the manual 1" bore from master power brakes. The pedal does have movement as I stop but it's comfortable for me. The pedal doesn't travel but maybe halfway and is very solid.

 I downloaded a brake math spreadsheet, from I can't remember where, it shows with 10.98" rotors, 2.75" caliper diameter and a 1" bore mc & with 127# of pedal pressure I get 1201# mc pressure on the rotors. Read somewhere one should have 1200# pressure for disc brakes. If I went with a 1.031" mc & the same 127# the mc pressure drops to 1130#. My pedal ratio is 7.43:1. At least for me, the car stops very well with the setup I have but I'm not as heavy with a 383 motor. I just guessing but I think the 440 is a little heavier than the 383.

 I did change to semi-metallic pads up front and the car does stop better. I haven't tried any other mc in the car.

[bc3j]

Forgot to mention brake torque. With 10.98" rotors I get a little over 5700. With 11.75" rotors it jumps to over 6100. Your better off with bigger rotors. All other factors remain the same but the torque increases with bigger rotors.

[stinger]

Thanks for the info,very helpful! I found an a body disc master with .0938 bore on summ for about 50 bucks that I'm going to try. like I said my fronts look to be all 70 setup and thats what I was told many years ago when I bought it,before the conversion brakes came out. rears are all rebuilt originals as well. if I dont like the set up then I'll probably spring for something better over the winter.
I just checked my records and found the MC I have now is the 1 1/32" bore unit so I think I'm headed in the right direction. I have very little pedal travel but if I two foot it the car stops fairly well but no where near what I want it. my 05 jeep has manual discs so I know what pedal feel I'm shooting for.
I need to drive this car,still seating in the rings 

[Katfish]

Check RockAuto or local parts store.

You can get a MC for a 75 Dart

[stinger]

installed the a bod mc 15/16" bore,much better. more pedal travel and a little better brake. I think I need to change out the organic pads to semi metalics though as I'm still not satisfied.