Another detail I need confirmed. On 1969 AIM UPC 5 A2 (Brake cylinder bracket assembly) item 11, 3781770 bumper is shown for pedal contact in non-depressed mode. If you compare to AIM UPC J50, A3 items 1.2.3. My question is should a car with a manual trans. and J50 power brakes have that bumper (item 11)? My car has M20 and pwr. disc and the pedal striker as shown in the AIM for J50. I do not have a bumper for either the brake or clutch pedal. I can understand the clutch pedal bumper missing as the car did a lot clutch bangging (drag racing), but was unsure if the brake should have this bumper or was it only used on manual brake cars? Just wanting to get details right. Thanks. Also, along this topic; Aim UPC J50, A4 shows item 3 Pipe and support for vacuum to booster for Big Block configuration. Could someone explain the difference or post pics of the two assemblys L34-5 Vs. L78 (3921927 vs.3921929)? I have one of these tubes and would like to know if it is the right one for L78 application. It seems to fit correctly, but there are no numbers on part and , again, I want it correct. I do not want to buy another if I don't need to. My part is GM original. Thank you CRG.