
Bench bleed the master cylinder....
Be careful ypu don't adjust it top far out. What you are doing is shortening the stroke slightly, but too much may cause the brakes tp start to drag.
What is you full combo again? What fromt and rear brakes? You might need to swap to the SN95 booster if you find pedal effort is much too high.

I have the same brake set-up also. With the 95 Boster and MC the pedal is firm, not overly firm, but the harder you push the harder is stops.
Just wondering.....but what route did you take for modifying the stock proportioning valve?
I used the MM kit that does away with the stock PV all together, and just have the PV for the rear brakes.

I'd always thought it was a no-no to reuse the Fox GT booster. Interested in seeing how this turns out as I have an 86 and pretty much everything I've read says it's a HUGE PITA to install the larger booster.
I'm not fond of the idea of having to beat and bang on the strut towers to get the damned booster to fit.

Just as long as you did the modification to the stock PV you're fine. They also sell a kit that comes with couplers and you completley do away with stock PV. Just one less thing in the engine bay.
Brake Proportioning Valve Eliminator kit, 1987-93 [MMBAK-6] : Maximum Motorsports, the Latemodel Mustang Performance Suspension Leader!

Honestly...I think you'll have to change the booster.
If you don't want to, you'll need a smaller mc to compensate.....like 94-95 cobra mc (15/16")
I think I've read where if you use the 93 Cobra MC you can get away with using the stock booster. Maybe if it was on a car with a stock motor and good vacum. I cant see where it would work real well on a car with a lumpy cam.
As far as installing the sn95 booster goes...it did take a little massaging of the strut tower, but you can't see it once the booster is in place. I also had to take off the upper intake manifold, and you have to elongate one of the mounting holes in the firewall to get it to mount up.
All in all it only took a couple of hours from start to finish to change out the booster. I had oringinaly tried without changing the booster because of the horor stories I had also heard, but it realy wasn't that bad.
5L5... this makes no sense to me. A LARGER MC would increase the mechanical advantage and make things easier on the brake booster. How does this compute?
What did you use to, "massage"?
Did it change the geometry of the tower at all?
You said you changed the booster because of horror stories. Does that imply that the stock booster was working well for you initially? How confident were you of that booster in the event of an emergency braking requirement?
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