how much vacuum?

carbed 85 gt

New Member
Mar 20, 2003
Honolulu HI
Hey guys I am diagnosing a stalling problem startup and want to rule out a vacuum leak. I have the trickflow track heat kit with the stage 1 cam 221 intake and 225 exh at .050 and 499 int and 510 exh lift. I installed the cam "straight up" and have an idle speed of 750 about with an auto.

I measured the vacuum at the vac tree on the spare spot thats blocked off and saw 11.5 to 12.5 in/hg of vacuum at idle. Does this sound right?
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stock should be 16-18 if i'm correct, so with that combo i'd say 12 average is OK..listen carefully around the intake for a hissing, or try some other vac. leak finding tips like propane, or carb cleaner..(or was it brake cleaner?) around the intake and notice if the idle changes or dies..a mechanics stethoscope with the metal rod removed so there's just a tube works good too for hearing those quiet hissing noises