68 Riviera Power Brake Booster

Hello Everyone,
So I am writing to find out if someone can help me with identifying what brake booster I would need and where to get it. I just did all brake drums and shoes and line all around, and want to do the master and the booster since the pedal still travels a lot. Thanks.
1st. off have you done any diagnostics to determine if in fact the booster is bad??? A low pedal could be caused by a variety of things & usually NOT caused by the booster.
Next thing to do is pump the pedal with the engine off to expel any left over vacuum in the booster. Now with your foot firmly on the brake pedal start the car. Does the pedal sink??? IF it does the booster is working properly. Does the car have 4 wheel drum brakes or discs up front???
From your description it sounds like 4 wheel drum brakes. If so it would be normal to have a low pedal just after replacing the brake shoes, unless they were contour ground on the car which I strongly doubt. Unless you brought the car to a real old time brake shop NO ONE has the equipment to perform the operation any longer. Were the drums re-surfaced??? IF they were what final OD did they end up at??? Law says no more than .060" oversize but you can go to .090" oversize as there is plenty off "Meat" on the drums. Most shops won't go past .060" because of the law & liability.
Were the drums replaced with the CHEAP China replacements??? No matter what the pedal will be low until the brake shoes break into the size of the drums whether they are new or old. I suggest driving the vehicle more. One thing I've ALWAYS adhered to was drive the car at 30MPH & do 30 normal easy stops gradually increasing pedal pressure 30 times. This should seat the shoes better to the O.D. of the drums & deposit some brake material to the drums. Did you use dot 3-4 or 5 brake fluid. Dot 5 has a tendency to aerate when pumping the pedal & takes some time to dissipate the air bubbles in the system. Try bleeding the brakes again after driving & ALSO re-adjusting the brakes.
Good luck.

Tom T.
Hello Sir,
Thanks for the reply. The master and booster are the original and both seem to be working well I was just replacing to achieve a fully changed system since I assumed they were the cause of the pedal drift. I am sorry I didn’t go into more detail. Yes I did bleed and the pedal went to the ground when started. So I will assume the booster and master are good. I do have drums fully around and the brakes don’t even kick in until the pedal is on the ground. This is my first classic rebuild so please forgive my limited knowledge. I am mechanically inclined and know about the engines and such, the braking system on these are the things that send me scratching my head. I did read the chassis manual and saw that I bled the brakes the wrong way as these recommend front driver side to the back so I will be redoing that. I will check out all the other items you brought up as well. Thanks.