carb selection help
Thread Starter
Instructor
Joined: Jan 2003
Posts: 237
Likes: 0
From: TAMPA FL
carb selection help
Just installed engine in chassis, I need advice on a carb.
Engine 383 9.8-1 comp.
Ported Sportsman II heads, 1.5 comp cams mag. rockers
Comp cams 280h hyd.
Edelbrock Preformer RPM intake
Hooker 1 5/8 Headers
I would like either a Holley or SpeedDemon.
Will I have enough Vacuum to run Vacuum secondaries.
Also can anyone give me and idea of HP and Torq. at the flyweel.
Any help appreciated, been away from the Vette/Hotrod business since 1982
Dennis
Engine 383 9.8-1 comp.
Ported Sportsman II heads, 1.5 comp cams mag. rockers
Comp cams 280h hyd.
Edelbrock Preformer RPM intake
Hooker 1 5/8 Headers
I would like either a Holley or SpeedDemon.
Will I have enough Vacuum to run Vacuum secondaries.
Also can anyone give me and idea of HP and Torq. at the flyweel.
Any help appreciated, been away from the Vette/Hotrod business since 1982
Dennis
Thread Starter
Instructor
Joined: Jan 2003
Posts: 237
Likes: 0
From: TAMPA FL
Re: carb selection help (73383)
Thanks on the hp and torq.
Can anyone tell me if I can run vacuum secondaries. I need to make up my mind and buy a carb. I need to get this baby fired upl.
Dennis
Can anyone tell me if I can run vacuum secondaries. I need to make up my mind and buy a carb. I need to get this baby fired upl.
Dennis
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
Re: carb selection help (73383)
Actually, vacuum secondaries open when the vacuum signal is low. So even though a performance cam may have less vacuum at idle, it shouldnt effect the function of the secondaries at full throttle. Full throttle is when the vacuum drops. 750 vac sec should work good.
Thread Starter
Instructor
Joined: Jan 2003
Posts: 237
Likes: 0
From: TAMPA FL
Re: carb selection help (73383)
Makes since to me. I had been thinking about an Avenger, but somewhere I was thinking I read something about big cams a mech secondaries and the reason for mech secondaries being loss of vacuum.
Dennis
Dennis
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Re: carb selection help (73383)
Thanks on the hp and torq.
Can anyone tell me if I can run vacuum secondaries. I need to make up my mind and buy a carb. I need to get this baby fired upl.
Dennis
Can anyone tell me if I can run vacuum secondaries. I need to make up my mind and buy a carb. I need to get this baby fired upl.
Dennis
:cheers:
Burning Brakes
Joined: Jul 2000
Posts: 963
Likes: 0
From: melbourne,Australia
Re: carb selection help (73383)
I have a strong 383 that has very high flo brodix heads and the Holley 750 vac sec works really well...the vac sec makes it much more friendly in traffic.....there is just enough vac to get the headlights up at idle,i think i have a minor leak in one of the headlight actuator seals,so there is probably plenty of vac without leaks.....the power brakes come off a separate line and there is plenty of vac for them.....john ;) :chevy
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Safety Car
Joined: Jun 2002
Posts: 4,844
Likes: 0
From: Pearland TX
St. Jude Contributor
Re: carb selection help (73383)
Dennis,
Getting any carb set up for your engine is probably the best trick. The out of the box carbs are just that.... out of the box stuff that is not set for any specific combination. Both Holley or Demon are good carburators that will work well with the limitations that are in that out of the box set-up. You'll get arguements both ways on mechanical & vacuum secondary set-ups. Those that live on the drag strip(or frequent it) agree that mechanical is the best way to go. You could go to 10 different carb specialists and get 10 different set-up recommendations based on what they found work for them. I plan on frequenting the drag strip and the people who built my carb gave me recommendations to go with a vacuum secondary 750 since I am working with a semi-stock transmission/convertor/stall setup that may not agree with the mechanical carbs. I am not a carb specialist.... that's why I paid someone else to make those decisions.
Getting any carb set up for your engine is probably the best trick. The out of the box carbs are just that.... out of the box stuff that is not set for any specific combination. Both Holley or Demon are good carburators that will work well with the limitations that are in that out of the box set-up. You'll get arguements both ways on mechanical & vacuum secondary set-ups. Those that live on the drag strip(or frequent it) agree that mechanical is the best way to go. You could go to 10 different carb specialists and get 10 different set-up recommendations based on what they found work for them. I plan on frequenting the drag strip and the people who built my carb gave me recommendations to go with a vacuum secondary 750 since I am working with a semi-stock transmission/convertor/stall setup that may not agree with the mechanical carbs. I am not a carb specialist.... that's why I paid someone else to make those decisions.