Hello

I just restored my 68 chevelle. At the time 8 months ago, I put in a rebuilt booster and masted from autozone. Finished the car, had no power brakes, nice firm pedal no difference when the car is running or not. I really got to push down for it to work, have all new brake lines new callipers, wheels cylinders, deffinatly the hydrolics are mint and totally bled.

Figured it was a bad brake booster, I had vacum going to it thought they just did a bad rebuilding job. A week ago i put a big block in the car. When the motor was out I returned the power booster for a new one. Just got the car running and on the road today. Same thing, no power brakes????

checked the vacum, perfect, I know the tests to see if its working and it deffinatly is not. the rod is on the lowe hole on the break pedal

Thank you for your help, not sure what to try next

You are running direct vacuum from a 3/8" fitting at the base of the carb right? What about the check valve located on the booster, when you pull it out of the booster with the engine running you should have strong vacuum. If you are positive that it is not a vacuum problem, then I would find another source for the booster. I am running this one on mine:
http://www.ss396.com/mm5/merchant.mvc?Screen=PROD&Store_Code=chevellecamino&Product_Code=FPB-1102&Category_Code=BOOSTER