holley 650 vacume help
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Junior Member
Joined: Nov 2005
Posts: 5
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From: washington
Car: 84 z28
Engine: 305 h.o 4bbl
Transmission: t5
Axle/Gears: 3.73
holley 650 vacume help
im switching out a ecm controled q-jet for a holley. i caint figure out where to hook my brake power booster to. there is no port in the rear of the carb like q-jet/elderbrock. the holley has only 2 other ports one at the base of carb for the vacume advance and one behind the front float bowl. i guess its not a carb question but what kinda vacume does the brake power booster require ported i assume ?
Joined: Mar 2000
Posts: 43,187
Likes: 46
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
The brake power booster requires full manifold vacuum and a fairly healthy-sized line. The factory uses 3/8", you should do the same.
Unless this is a double-pumper carb, you really shouldn't change from the factory q-jet.
Unless this is a double-pumper carb, you really shouldn't change from the factory q-jet.
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