BG Demon v. Street Avenger
Thread Starter
Racer
Joined: May 2001
Posts: 394
Likes: 0
From: Jackson, MS USA
BG Demon v. Street Avenger
First, thanks to all for all the help on my last post about carbs in the early fall. I was trying to decide on a Holley or a Edlebrock. With the help of Brettmc, I kept my Holley 650 limping along. The ol' girl (Holley 650) is worn out, and in bad shape, ask Brettmc 
. I have decided to go the square bore route, and am trying to decide between a Street Avenger and a BG. I have a 350 (nm) at 30 over with a fairly large cam (thanks bubba), headers and a 4-speed. I am going to go with a 750 (BG) or the 770 (Holley). Can anyone give me the pros and cons of both. I want the best performance, and I am not afraid to work on the carb, but I do not want to have to tune it everytime I crank the car. All I have ever owned (performance wise) is Holleys, I just do not have any experience with the BGs.
. I have decided to go the square bore route, and am trying to decide between a Street Avenger and a BG. I have a 350 (nm) at 30 over with a fairly large cam (thanks bubba), headers and a 4-speed. I am going to go with a 750 (BG) or the 770 (Holley). Can anyone give me the pros and cons of both. I want the best performance, and I am not afraid to work on the carb, but I do not want to have to tune it everytime I crank the car. All I have ever owned (performance wise) is Holleys, I just do not have any experience with the BGs.
Racer
Joined: Oct 2005
Posts: 267
Likes: 0
From: Orlando FL
Sorry, fellas but I couldn't resist! I'll keep it as "low key" as possible, I promise. Throw that Holley in a nearby lake, run like your hair is on fire and don't look back! Ok...............so I failed, members.
Seriously, Money pit, I used Holley's exclusively until just recently switching over to a BG carb because I was told by my mechanic that the machining and thus, calibration and fuel mixture accuracy is much better on a BG than a Holley. Although my Holley had VERY low usage on it, my big block never ran very smoothly and cleanly with it and I thought the switch was worth a try. My 454 is hopped up fairly extensively but even before I put all the work into it, it ran the same way, jetting wise. It took a while to warm up enough to run without me playing with the throttle and when it was warm, it never pulled smoothly below 2000 rpm. It was running rich and was never able to be tuned to run cleanly. After the switch, the car starts much more easily, runs cleanly even cold, can idle at 800rpms (646" lift, 246 duration @ .050 solid roller cam) and pulls strongly and cleanly from idle on up. It was a massive improvement over the Holley. I wish you the best of luck and hope my information helps you buy the vastly superior carburetor.
P.S. Get one with annular boosters
Seriously, Money pit, I used Holley's exclusively until just recently switching over to a BG carb because I was told by my mechanic that the machining and thus, calibration and fuel mixture accuracy is much better on a BG than a Holley. Although my Holley had VERY low usage on it, my big block never ran very smoothly and cleanly with it and I thought the switch was worth a try. My 454 is hopped up fairly extensively but even before I put all the work into it, it ran the same way, jetting wise. It took a while to warm up enough to run without me playing with the throttle and when it was warm, it never pulled smoothly below 2000 rpm. It was running rich and was never able to be tuned to run cleanly. After the switch, the car starts much more easily, runs cleanly even cold, can idle at 800rpms (646" lift, 246 duration @ .050 solid roller cam) and pulls strongly and cleanly from idle on up. It was a massive improvement over the Holley. I wish you the best of luck and hope my information helps you buy the vastly superior carburetor.
P.S. Get one with annular boosters
Last edited by Grutzy; Dec 29, 2005 at 08:27 PM.
Safety Car
Joined: Oct 2000
Posts: 4,282
Likes: 172
From: Lake Wylie, South Carolina
I cannot tell you from first hand experience about the BG carbs but I have been doing a lot of homework and am convinced that the BG carb is now the way to go. I have worked on Holley's for years and used to sell them when I worked at SuperShops in the mid 80's. I want to stress the words "WORKED ON" when refering to Holley's. That is all everyone I knew did was work on them and some of these guys were involved with NASCAR teams. When comparing the BG's to the Holley's in cost , appearence and performance I think the BG's win out in all categories. The choice is ultimately yours. Good Luck!!
Burning Brakes
Joined: Apr 2000
Posts: 1,145
Likes: 1
I have a BG 750 Vac secondary electric choke for sale if you are going that route. I ran it for quite a while on my 350 before I went with a mechanical secondary on my 383, so there are none of the 'bugs' to work out that you may here of. And as far as having to tune it reqularly, once I dialed it in, I never had an issue.
box,video,tuning guide, its all there, just as new. $300.
Chris
box,video,tuning guide, its all there, just as new. $300.
Chris
Thread Starter
Racer
Joined: May 2001
Posts: 394
Likes: 0
From: Jackson, MS USA
Chris/71roadster,
I left you a PM. I am interested. Thanks for all of the advice guys, I love the forum. Also, Grutzy, did you switch to annular boosters, or were they stock on your carb.
I left you a PM. I am interested. Thanks for all of the advice guys, I love the forum. Also, Grutzy, did you switch to annular boosters, or were they stock on your carb.
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Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by blackbeauty74
Which is best for a 4 speed vac or mec secondary? and why?
i have vacuum secondaries because i thought it would be the way to go for a smooth cruiser with the 700r4....i will never buy vacuum secondaires again because i want the pure rush of the mechanical linkage....i will not get rid of the carb with the vacuum secondaries i just will not buy one again
Safety Car
Joined: Oct 2000
Posts: 4,282
Likes: 172
From: Lake Wylie, South Carolina
Does anyone have this MSD distrbutor? Opinions? Other options?
Keep in mind that I do not have a distributor at all since I sold off the sb that was in the car before building the BB. I still have the mechanical tach so that is another consideration for what type of distributor to run. There is also always the option of swapping out to aftermarket guages.
Opinions, thoughts ideas?
MSD Distributor
Opinions, thoughts ideas?
MSD Distributor
:o
Burning Brakes
Joined: Apr 2004
Posts: 847
Likes: 0
From: Des Allemands LA
20 minutes with a 750 Mighty Demon on my car and it ran sooo much better than with a Holley I had put cosiderable time into. The holley 750DP I had finally straightened out and the motor ran decent, however when I put the Demon on, the motor ran about the same with no adjustments. Set the idle and vacuum and holy S#*T Bat-Man it's ALIVE. To put the icing on the cake I pulled the fuel bowls to do a jet change while tuning a little and the craftsmanship of the billet parts is awesome. It almost looks like the metering plate and mainbody are one piece. If you can't tell I'm with the Demon Crowd here.
ltlevil
ltlevil
Melting Slicks
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
Look's like I'm going to be the voice in the wilderness. I have no BG experience but have been running a 670 Street Avenger straight out of the box for more than 3 years. No complaints here except that I had to replace the plastic sight windows with brass plugs. Seems to work just right for my mild 355.
Thread Starter
Racer
Joined: May 2001
Posts: 394
Likes: 0
From: Jackson, MS USA
ALLCON, Thanks for the advice. I got some good info, and a potential source for a carb. My only problem now is, is the vac secondary right for me. With my 4 speed, I am having mixed emotions about the vac sec. I have had good luck with the mechanical, but I am thinking of tryin the vac sec out. I am know carb expert, and probably would not know the difference in performance right away.
Blackrat,
no probs, I do not really believe in that whole "you hijacked my thread crap" talk about what you like, that is how we expand our knowledge, especially if it is remotely related to the topic
Blackrat,
no probs, I do not really believe in that whole "you hijacked my thread crap" talk about what you like, that is how we expand our knowledge, especially if it is remotely related to the topic
Racer
Joined: Oct 2005
Posts: 267
Likes: 0
From: Orlando FL
marshrat, if you have noticed, everybody who advocates the use of a Holley has never used a Demon. Notice how the people who have switched to a Demon, rave about the improvement. One can hide his head in the sand and pretend life is just perfect in Holleywood. However, those of us who have roamed past the glitter and hype have seen the light and are relishing in the riches of glorious carburetion.
Melting Slicks
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
Originally Posted by Grutzy
marshrat, if you have noticed, everybody who advocates the use of a Holley has never used a Demon. Notice how the people who have switched to a Demon, rave about the improvement. One can hide his head in the sand and pretend life is just perfect in Holleywood. However, those of us who have roamed past the glitter and hype have seen the light and are relishing in the riches of glorious carburetion.
AKA, if all you've had is vinegar then you can't appreciate honey.
Safety Car
Joined: Jul 2002
Posts: 3,770
Likes: 3
From: St Louis MO
Definitely go with the DP over the VS with the 4-speed and the big cam. As far as brand, you should buy what you are familiar with, or what you know how to work on. With the right knowledge, a Holley can be tuned to run right on just about any SBC or BBC engine. I've got a couple of books you can borrow if you want that will really give you the knowledge you need to properly tune a Holley or a BG. I've totally gone through my 850 using what I gained in these books and I must say it runs really strong.
How's that for appearance? (do you think I would let a carb leak gas all over that polished AirGap??) If you are familiar with Holleys, there is no need to follow the herd and go to BG. If you know what you are doing, Holleys do NOT need to be constantly fiddled with but it has to be done right on the front end. My carb pulls strong down low (thx to the annulars), up top, idles smooth, requires minimal throttle feathering while cold, doesn't leak and holds it's settings. What more can you want?
Brett
How's that for appearance? (do you think I would let a carb leak gas all over that polished AirGap??) If you are familiar with Holleys, there is no need to follow the herd and go to BG. If you know what you are doing, Holleys do NOT need to be constantly fiddled with but it has to be done right on the front end. My carb pulls strong down low (thx to the annulars), up top, idles smooth, requires minimal throttle feathering while cold, doesn't leak and holds it's settings. What more can you want?
Brett
Racer
Joined: Oct 2005
Posts: 267
Likes: 0
From: Orlando FL
My BG does not require ANY throttle feathering when cold. My Holley would not run without doing so when cold. When I ran my Holley in the garage with the door open, my eyes would water and burn from the exhaust. Not with the BG. My car hesitated between idle and 2000 rpm's with the Holley. It runs cleanly everywhere with the BG, without any hesitation whatsoever.
Melting Slicks
Joined: Dec 2004
Posts: 2,161
Likes: 0
From: pr, frederick md.
all this is very interesting because ive had nothing but problems from my 850 speed demon. for starters i had to tighten both fuel bowls right out of the box cuase they were near falling off, and later had to fix the secondary arm because it bound so much the secondarys could not open. since then i have not been able to tune this turd for a bad off/on throttle skip/surg. and when i let off to coast, my whole car jerks. i want to throw this thing in the garbage 