68 Charger multiple brake issues

[BDnFL]

Originally power drum all around.
Converted to disc front drum rear by shop. Wilwood front disc with master cylinder. New drums in rear.
Thanks to a member here I see I have an A Body booster with a stand-off from firewall. See pic.
Brakes terrible so I started investigating and found Residual Valve in backwards.
I then pulled master cylinder to check rod length. Rod at least 1/8 long. With it adjusted all the way in.
So here is my questions: Can the A body booster be used?
With master cylinder removed I lightly pressed brake pedal and felt a spring tension on pedal, is this normal ?
Summit does list the A body style with firewall stand-off bracket for B body.
Hopefully it can be used because repiping the master and proportional might be beyond my scope due to access.
Thanks

 

[Sixpactogo]

I put one of those POS boosters on my Niece's 70 Challenger years ago when I restified it. I don't know why they even sell them with the belief they are usable. I doubt anyone would be happy with their performance. I believe you need the dual 8" Bendix unit that the factory installed on these cars when they went to front discs. I swapped one in her Challenger and another one on my 68 Charger. Both work great! The only deviation from the factory units are the boots on these are slightly larger and require a bit of enlarging the firewall hole with a dremel tool or file. Brakes are way too important to be miss-matching parts hoping they will play well together. They seldom do.

https://www.ebay.com/itm/235679793717?

 

[BDnFL]

I put one of those POS boosters on my Niece's 70 Challenger years ago when I restified it. I don't know why they even sell them with the belief they are usable. I doubt anyone would be happy with their performance. I believe you need the dual 8" Bendix unit that the factory installed on these cars when they went to front discs. I swapped one in her Challenger and another one on my 68 Charger. Both work great! The only deviation from the factory units are the boots on these are slightly larger and require a bit of enlarging the firewall hole with a dremel tool or file. Brakes are way too important to be miss-matching parts hoping they will play well together. They seldom do.

https://www.ebay.com/itm/235679793717?

Sixpactogo,
Thanks for replying. I had read some of your previous posts on this booster being junk. I was hoping this wasn’t one.
With the booster in your link can I still use my current Wilwood master cylinder and proportioning valve?

 

[68 Sport Satellite]

There seems to be a flurry of FBBO members with brake system issues in the last month. Watching this one with interest...

 

[Sixpactogo]

Sixpactogo,
Thanks for replying. I had read some of your previous posts on this booster being junk. I was hoping this wasn’t one.
With the booster in your link can I still use my current Wilwood master cylinder and proportioning valve?

I'm not up to speed on Wilwood parts so no help for you there but I would think they would require the same amount of pressure to operate. Most issues with swapping drums for discs involve not knowing that disc brakes require double the amount of pressure and try using a drum booster. I had to learn that lesson myself years ago. With all of the threads on this site involving these swaps, I know I am not alone. Neither are you.