loss of vacuum with newer carb

08-17-2008, 02:20 AM
i just switched a 2 barrel carb for a 4 barrel carb on my 66 dynamic 425 auto.
now i dont have enough vacuum to operate my brakes properly. i cant find any leaks anywhere. does the 4 barrel produce less vacuum than the 2? or what else could cause it and what are the remedies. thanks

08-17-2008, 10:15 AM
Welcome to AF, no it does not as long as the secondarys are completely closed, I assume you have the correct carb on the correct intake? If you suspect a leak around the base or secondarys, get a Bernzomatic type propane cannister with a nozzle and go around the carb and base gasket see if the idle changes, if you have a vacuum leak as we speak the engine would be running rough, no? Is the pwr brake vacuum hose connected to a main intake source? Lots of questions back, right?

08-17-2008, 10:33 AM
Thier is also a vacum canister on the firewall that sometimes rusts out and causes low vacum, I had this prob on my 66 Olds Dynamic 88 w/425 ;).
I'd double check those vacum lines for cracks too. :2cents:

08-17-2008, 02:36 PM
Good point, I assumed he would hear that, forgot about that car having one.

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