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07-20-2022, 11:21 PM | #1 |
Registered User
Join Date: Dec 2012
Location: Temple City
Posts: 3,560
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Always buy a good carb.
I have had the cheap Holley 750 vacuum secondary with jets on both ends. My engine is a 5.7 or 350 2nd generation LT1 with AFR 190E heads, gmpp intake, and a Pertronix distributor. Compression is 10.7-1, and a Comp 306 cam.
No matter how I tuned it never felt right. Not bad, but not right. Although it was fine for DD. Which is where I was aiming. Well today I put a original Demon 750dp street model on it, and rough tuned it. Which I just rebuilt this week to put around on for fun. While it is running pig rich at 11.5 afr pretty much everywhere. Which I returned the 4 corner idle to lean out a hour ago, and took a jet out. I have to see where sits at tomorrow morning. It honestly felt like I picked up 10-15 hp, and the responsiveness was just up everywhere. Plus the afr swing was much tighter then with the vacuum secondary. So if my thoughts work out I should be able to atleast match or maybe even beat its current highway mpg average. City will always be in the toilet due to the cam selection. Besides the jets. I am also going to dial in the accelerator pump since this carb seems less dependent on it vs the Holley 750 vacuum secondary for good drivibility. So to whomever is still into carbs like I am. Always get the best one you can afford. You won't go wrong especially at tip in for passing power. |
07-21-2022, 11:14 AM | #2 |
Moderator
Join Date: Aug 2011
Location: China Spring, TX
Posts: 7,280
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Re: Always buy a good carb.
I have a Street Demon 625cfm. Pretty well known around the net that they come fat which mine was. I changed the jets to 78's and played with the metering rods and now get 16mpg. For my engine and all I'd say I'm pretty pretty happy.
I like the passing power. Around here your either being passed or passing.
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Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats? |
07-26-2022, 09:11 PM | #3 | |||
"I ain't nobody, dork."
Join Date: Sep 2007
Location: Whidbey Island, Washington
Posts: 8,921
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Re: Always buy a good carb.
Quote:
Gary
__________________
'cuz chicks dig scars... My 1972 GMC 1500 Super Custom (Creeping Death) "long term" build thread. The Rebuild of Creeping Death after the wreck Quote:
Quote:
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07-27-2022, 09:11 AM | #4 | |
Registered User
Join Date: Dec 2012
Location: Temple City
Posts: 3,560
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Re: Always buy a good carb.
Quote:
If my reading of carbs is right. Every sub model gets different air bleeds among other details. Which in my case never let it perform right. Work good yes, but not perform. |
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07-28-2022, 07:24 PM | #5 | |||
"I ain't nobody, dork."
Join Date: Sep 2007
Location: Whidbey Island, Washington
Posts: 8,921
|
Re: Always buy a good carb.
Quote:
Gary
__________________
'cuz chicks dig scars... My 1972 GMC 1500 Super Custom (Creeping Death) "long term" build thread. The Rebuild of Creeping Death after the wreck Quote:
Quote:
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