Demon Carb and Vacuum
Thread Starter
Racer
Joined: Jul 2008
Posts: 446
Likes: 1
From: Cary NC
Demon Carb and Vacuum
I bought a new Demon Crate Engine Carb for my 330/350 engine. I am replacing a Holley. The Holley had 2 large vacuum ports but the Demon only has one. Would it be okay to use a tee to hook up the brake booster and PCV into the one port? Also Autozone doesn't have air cleaner studs that fit Demons (5/16), can I just go to Lowe's and pick up a 5/16 screw and use that?
Thanks,
Michal
Thanks,
Michal
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
I bought a new Demon Crate Engine Carb for my 330/350 engine. I am replacing a Holley. The Holley had 2 large vacuum ports but the Demon only has one. Would it be okay to use a tee to hook up the brake booster and PCV into the one port? Also Autozone doesn't have air cleaner studs that fit Demons (5/16), can I just go to Lowe's and pick up a 5/16 screw and use that?
Thanks,
Michal
Thanks,
Michal
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Burning Brakes
Joined: May 2006
Posts: 774
Likes: 1
From: Round Rock Texas
What size Demon did you get? I have a 750 Speed Demon. I used an AirGap RPM and it has a port on it for vacuum. get ready to do some tuning. I went through 3 jet size changes before it finally dialed in, but I love the carb.
Keep us informed on how it goes.
Keep us informed on how it goes.
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
Thread Starter
Racer
Joined: Jul 2008
Posts: 446
Likes: 1
From: Cary NC
The carb is a 650 cfm. I don't think there will be too much tuning as this carb is designed specifically for my engine. http://www.jegs.com/i/Barry+Grant/13...VC330/10002/-1
Where would I buy the tee? Lowes? What size? Also where could I get some more of that large vacuum line. I'm hoping to be done with my mini restoration this weekend and I'll post pics. Next year she gets paint and a rear suspension rebuild.
Where would I buy the tee? Lowes? What size? Also where could I get some more of that large vacuum line. I'm hoping to be done with my mini restoration this weekend and I'll post pics. Next year she gets paint and a rear suspension rebuild.
Burning Brakes
Joined: May 2006
Posts: 774
Likes: 1
From: Round Rock Texas
The carb is a 650 cfm. I don't think there will be too much tuning as this carb is designed specifically for my engine. http://www.jegs.com/i/Barry+Grant/13...VC330/10002/-1
Where would I buy the tee? Lowes? What size? Also where could I get some more of that large vacuum line. I'm hoping to be done with my mini restoration this weekend and I'll post pics. Next year she gets paint and a rear suspension rebuild.
Where would I buy the tee? Lowes? What size? Also where could I get some more of that large vacuum line. I'm hoping to be done with my mini restoration this weekend and I'll post pics. Next year she gets paint and a rear suspension rebuild.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Instructor
Joined: Jan 2007
Posts: 232
Likes: 41
From: Simpsonville SC
The carb is a 650 cfm. I don't think there will be too much tuning as this carb is designed specifically for my engine. http://www.jegs.com/i/Barry+Grant/13...VC330/10002/-1:
Thread Starter
Racer
Joined: Jul 2008
Posts: 446
Likes: 1
From: Cary NC
I bought one of the 1282010C double pumper for my Vortec also. After checking its setup, it has the same jetting and setup specs as a regular 650 Speed Demon with the exception of the electric choke added. So, I’m not convinced BG actually ‘tunes’ it for a 330/350 Vortec crate.
Instructor
Joined: Jan 2007
Posts: 232
Likes: 41
From: Simpsonville SC
I'm pleased with it so far. It's setup close out of the box. I have a very slight off idle lean spot that I need to work on. I have a LM-2 i'm using to dial it in. My setup is an L-82 with Vortec heads and a Comp Magnum 270 cam. You will need a heat shield as described in Lars Speed Demon install paper.
Tech Contributor
Joined: Aug 1999
Posts: 14,377
Likes: 6,377
From: At my Bar drinking and wrenching in Lafayette Colorado
You can e-mail me for my BG setup and installation papers - the BGs are not set up well out of the box:
V8FastCars@msn.com
Lars
V8FastCars@msn.com
Lars
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
Just got off the phone with BG, They recommend NOT to "T" into the brake line, the tech there told me your brake booster will get full of oil mist also if you do that.
So, what i am going to do is order a 1/4" Carburetor Spacer, Phenolic, 0.250 in. Thick, 4-Hole, by Canton. and then tap a port in it that comes out the center for my PVC Vacuum.
BG said this is the best way to do it...
So, what i am going to do is order a 1/4" Carburetor Spacer, Phenolic, 0.250 in. Thick, 4-Hole, by Canton. and then tap a port in it that comes out the center for my PVC Vacuum.
BG said this is the best way to do it...
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
I feel your pain... with the biggest drop cleaner I can get and currently running a 1/2 spacer for heat reasons, with a 3" air cleaner, I am at 1/8"
.... running a Edelbrock RPM and a BG Mighty Demon.
Now, I found and ordered a Carburetor Spacer, Phenolic, 0.250 in. Thick, 4-Hole, Square Bore from Canton...(I have there oil pan.. Great pan great price)
This will give me another 1/4" when I remove the 1/2"....Giving 3/8" hood clearance, up front on air cleaner, twice that back side.
Anyway, I am going to bore a hole and tap it down the middle and then tap it open in the center for an even tap on vacuum .... wow... i used thoes words over a lot??/
.... running a Edelbrock RPM and a BG Mighty Demon. Now, I found and ordered a Carburetor Spacer, Phenolic, 0.250 in. Thick, 4-Hole, Square Bore from Canton...(I have there oil pan.. Great pan great price
)This will give me another 1/4" when I remove the 1/2"....Giving 3/8" hood clearance, up front on air cleaner, twice that back side.
Anyway, I am going to bore a hole and tap it down the middle and then tap it open in the center for an even tap on vacuum .... wow... i used thoes words over a lot??/
Intermediate
Joined: Jul 2008
Posts: 41
Likes: 0
From: Raleigh NC
What did you end up at front and rear?
