If it holds vacume for a day or two or more and w/out the motor running there's enough vacume for one normal application of the peddle but it gets stiffer on the second and solid on the third can you conclude that the canister is not leaking.

Reason I ask is because when the engine's running the brakes seem to run out of vacume easily - like two or three quick peddle applications and it's gone.

Also, there is inconsistent peddle pressure when the motor is running and I apply sustained pressure to the peddle.

Thanx.

 

IMHO if the booster still has vacuum after a couple days then there is no problem there. Are you still running the stock cam? It sounds like the vacuum source for the booster can't keep up.

Tim

 

Yeah it's a stock 83 LG4 except for headers and 11 degrees of advance.

Recently had a TH350 installed so maybe wherever they sourced the vacume from for the tranny is causing some problems and it can't keep up as you've suggested.