Vacuum question on 406 with big cam...
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Instructor
Joined: Oct 2001
Posts: 104
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From: Tucson AZ
Vacuum question on 406 with big cam...
Hey does anyone know if this is normal? My dad has a 406 small block with a pretty radical cam (I think its around 300 degrees duration or so) and he has an off idle stumble. Vacuum gauge reads about 7 lbs at idle and then when he opens the throttle blades on the 650 barry grant it drops to 0. He is going to put a reserve canister on to see if that helps. Where is a good place to tap in for a vacuum T? It has power brakes as well. Any helps is appreciated guys, thanks James
Pro
Joined: Jun 2001
Posts: 683
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From: Calgary
Re: Vacuum question on 406 with big cam... (Dracula383)
Normally, stumbles or hesitations are a sign that the engine isn't getting enough fuel. Check the accelerator pumps for excessive clearance, or maybe you need larger squirters or a different cam.
Edit: By different cam, I mean the cam on the accelerator pump arm.
[Modified by 74vetteman, 11:41 PM 8/21/2003]
Edit: By different cam, I mean the cam on the accelerator pump arm.
[Modified by 74vetteman, 11:41 PM 8/21/2003]
Race Director
Joined: Mar 1999
Posts: 10,258
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From: Calif.
Re: Vacuum question on 406 with big cam... (Dracula383)
Hey does anyone know if this is normal? My dad has a 406 small block with a pretty radical cam (I think its around 300 degrees duration or so) and he has an off idle stumble. Vacuum gauge reads about 7 lbs at idle and then when he opens the throttle blades on the 650 barry grant it drops to 0. He is going to put a reserve canister on to see if that helps. Where is a good place to tap in for a vacuum T? It has power brakes as well. Any helps is appreciated guys, thanks James
