Vacuum Booster or Not?

I found another thread that has a lot of useful info on the subject.

http://www.forabodiesonly.com/mopar/showthread.php?t=27864&highlight=master+cylinder+push+rod

In this thread member redfastback recommends the same master cylinder, although again the application is not the 4 piston kelsey hayes calipers.

The thread concludes that the push rod from the manual brakes was reusable with the new master cylinder. But the car was not a 65.

I got busy and pulled the old master cylinder off the firewall and removed the push rod. Then I installed it into the master cylinder that came off a 72 Dart with power disc brakes. Not sure if it's the right one for that application, the bore is 1 1/32. The rod fit tightly into the master cylinder using the same rubber bushing from the 1965 master cylinder.

DISREGARD - SEE POST 17

The problem came when I hooked the push rod to the brake pedal. It was too short so that the brake light switch was not engaging. It would take at least 3/8" longer rod to fully engage the brake light switch at the end of travel. If I go without the booster, I will need to find a longer rod or lengthen the one I have by probably 1/2" Currently it's 6" from the center of the pin to the end of the rod.

Then I installed the vacuum booster on the firewall with the same master cylinder. Again when I went to hook up the brake pedal to the linkage, it was too short, this time by about 5/8". So if I decide to use the booster, I will have to lengthen the linkage by probably 3/4".

END DISREGARD

Having seen what the engine compartment looks like with the big old booster in there, I am highly motivated to try the small bore master cylinder. The master cylinder is very close to the breather it rubs the A/C lines at the front.

I would feel better if I could find someone who has used that master cylinder with Kelsey Hayes front disc brakes and no booster.