Replacement brake master cylinder

[Racer57]

70 Cuda, 383cu, manual tranny, front disk, rear drum

My master cyl may have a leak at the rear seal. But I have to do some more checking when it warms up. The picture shows what I have including what I've been told is a Midland Ross booster. If I do have to replace it with new (not messing around with rebuilding) is there a better master cyl/booster combo, better than what I have and the hyd lines would still hook up too ? I have zero luck in forming brake lines. 

[tman]

You have a few choices from Rockauto.com  Raybestos or Centric

https://www.rockauto.com/en/catalog/plymouth,1970,cuda,6.3l+383cid+v8,1231737,brake+&+wheel+hub,master+cylinder,1836

[JH27N0B]

You have a few choices from Rockauto.com  Raybestos or Centric

https://www.rockauto.com/en/catalog/plymouth,1970,cuda,6.3l+383cid+v8,1231737,brake+&+wheel+hub,master+cylinder,1836

I'm not satisfied with any of what they're showing.  The 36221 is a drum brake MC, definitely don't use that!  36283 will work, it's actually an aftermarket version of the B body disc MC.  It's got a 1-1/8" bore.  In 70, E body were all 1" bore except hemi disc.
I used one of those on my Challenger convertible for a time before I restored an original MC to put on it.  The pedal was firmer than I liked, and if I braked hard the rears would start locking up.  Whatever the case, I drove the car with it for a couple years without crashing. 
I'd recommend the 36307.  It's the equivalent to the OEM for 71-74 and has a 1-1/32 bore.
https://www.amazon.com/Raybestos-MC36307-Professional-Master-Cylinder/dp/B000C6ZY8U
What MC is on it now?  Is it an original Bendix with "thermometer" style front? If its casting number is 2229171, don't toss it, it's worth a small fortune.
The booster is a replacement.  OEM in 70 into early 71 was Bendix.

[Racer57]

While I'm on the subject, whats the best speed bleeder ?

[JH27N0B]

To bleed just the master cylinder to install it, or your whole system?
I have a nice MC bleeder Kit I got ages ago with different thread fittings and tubing. Thread the fittings in each outlet, put the tubes in the reservoirs, fill, then keep pumping the brake pedal or on a bench cycle the pistons, watching the fluid in the tubes until no more bubbles.

[Racer57]

To bleed just the master cylinder to install it, or your whole system?
I have a nice MC bleeder Kit I got ages ago with different thread fittings and tubing. Thread the fittings in each outlet, put the tubes in the reservoirs, fill, then keep pumping the brake pedal or on a bench cycle the pistons, watching the fluid in the tubes until no more bubbles.

Doesn't air get in the lines when their removed from the MC, then reconnected ?

[JH27N0B]

No, other than maybe a insignificant trace of air.