I'm getting ready to installed my Speed Demon on my SBC 400, I remember that some advise taking the Demon apart before bolting on because of flaws of metal shaving in the carb. This reminds me of my AFR heads with the shaving. Nothing is just a bolt on and go but i'm desperate to see what Demon has to offer compared to the 3310, hopefully the Demon will be superior to the Holley 3310. After the test I can sell one on Ebay.
SBC 400
280/284
247/251@.050
500/504 lift
110/106
rear end 3:73
Tranny: 700R4
Comp: 10:4:1
The reason for the carb change was that my 3310 lacked the power of DP 4779 when my engine was dynoed.

Hey David,
How are you planning on testing the Speed Demon against your 3310? 1/4mi, SOTP or dyno again possibly? I've talked to you a couple times now as my setup is quite close to yours. I can't wait to hear how your car runs down the 1/4 once you have it tuned a little. Us thirdgen Camaro guys need to stick together graemlins/beers.gif

i have used both and its just my opinion stay with the holley

thirdgen Camaro guys :confused: :eek:

Robert,
amongst all you big block full bodied cars we're just little tots tongue.gif

3rd generation would be '82 - '92 fbodies

I just finish taking it apart ewithout finding all the junk other claim they have found, I guess BG has cleaned up their act. Basically I just blew air through all opening and cjeck for metal shaving. While I had it apart I went ahead and set the butterfly .020 and screw the Idle Eze 1 1/2 turns out so that I can have a good base for starting. I will not install the carb until my new Auto Meter Temp Guage gets here. I have tried the Sunpro guages from Autozone and they are pure junk. Sunpro have a tendency to go out at the wrong time, so I change all my gauges to Auto Meter.

I tried a new 750 speed demon and was very disapointed. My 3310 gave me faster 1/4 mile times. I called the tech guys to complain and all they could say was that their speed demon was intended for big blocks and there was nothing I could do to get this carb to run as fast as my Holley 3310. They told me that I had to buy the 650 "mighty demon" to get my 1/4 times back down. I just sold the speed demon to a big block guy, swore never to get another Barry Grant carb, and put together a double-pumper 750 Profom carb. I used the proform main body, metering blocks, holley base and bowls. My engine then turned the fastest 1/4 mile times in its history. I have a 388 stroker.
Daniel

Apparently the shavings are in the metering block so removing the jets and anything else stuck in there would be advisable then blowing it out.

There was a debate about Holley VS. Demon on another board.In this debate a professional carb builder/tuner stated that he personally wouldn't run anything less than a Mighty Demon because of quality issues and tuneability with the lower models.

When cam duration starts getting above 220@.050 the need for the Mighty Demon becomes necessary. Give the Tech Hotline a call. They are very good. The 750 Speed Demon is recommended for 468 and larger engines with mild cams.

Just razzing ya 91, since this is mainly a Chevelle board :D but there is some good all around info in this section. I like the first gen Camaros and would trade my Chevelle in a heartbeat for one in the same condition as my car, they just made the doors too big on the latter generations.

I have two carburetors in my possession: 1) Speed Demon 750 Mech. 2) Holley 750 Vac Sec.
This is a weekend warrior that is used for cruising during the summer, however I would like to have maximum performance for the street and maybe a few runs at the drag strips with the joy of breaking into the mid 11 sec. This engine dyno with two different carbs and the 4779 won hands down. How would you compare the Speed Demon 750 Mech. VS Holley 3310VS

Holley 4779- jets:70/80 timing: 34
Torque Horsepower
502@ 4300 464@ 5800

Holley 4779- jets:70/80 timing: 32
Torque Horsepower
495@ 4300 455@ 5600

Holley 3310VS jets: 72/75 timing: 36
Torque Horsepower
484@ 4600 467@ 5900

Holley 3310VS jets: 72/75 timing: 34
Torque Horsepower
479@ 4700 459 @ 5600

Holley 3310VS jets: 72/75 timing: 37
Torque Horsepower
481@ 4600 457@ 5700

Here ar the specs of my engine:
My SBC 409

Engine Block: 400 SBC ID# 330817/14y139664/ T0508CSU
(4.125 bore X 3.750 stroke) after .040 bore (4.165 bore x 3.75 stroke =409)

Deck Plate Bored, Mains Align Honed, Block Deck .002, Deck Plug Holes & Tap w/3/16 Holes, Starter Bolt Drilled, Front Three Gallery Plugs Tap for ¼ Pipe Plugs.

Crank: Scat 4340 Crank 3.750 6.00, Internally Balance, Part# 4-400-3750-6000

Bearing: Clevite– MS1038H Mains and CB663H Rods

Piston: Wiseco Pistons, .040 over, 5.4cc; 430 grams, Part# PT020H4

Rods: Eagle ESP 4340 H-Rods 6.0, Part# CRS6000B3D

Block: Zero Deck: 0.002

Compression Ratio: Static-10:44 Dynamic-8:27

Cam: Grind: Solid Lunati/ (Recommended by Harold Brookshire) 280/284F10 .525/.530 Lift, 247/251@.050, 159/162 at .200, .500/ 504 valve lift, 2500-7000 RPM, Installed Straight up, .026" Valve Lash Hot, .026 Adjustment Range: .018" to .030" Hot.

Valve Springs: Lunati Part#73124 130 Seat 330 Open.

Heads: AFR 195 Part# 1035 w/23º valve angle, 74cc, drilled steam holes.

Head Gasket: Fel-Pro-1014 / .039 in. compressed thickness, 4.200 in. bore, 9.0 cc compressed volume

Intake: Edelbrock RPM #7101

Carb: Speed Demon 750 Mechnical

Rear End Gear: 3:73

Transmission: Pro-Built Street/Strip 700R4

Stall Converter: A.C.T. 3000 Stall

Exhaust:
Hooker Super Comp headers 1 5/8 Headers part # 2460-1 ceramic coated;

Hooker Super Competition high flow cat-back exhaust system, Intermediate pipe: 3 in.
* Tail pipe diameter: 2 1/2 in.
* Dual tail pipes out the rear under the bumper

Looking at this combination do you think will be the "right" carburetor for my application or what would you recommend.

Thanks: David

RObert,
well since I've started hanging around here with all you guys I've attained much more respect for the Chevelles, Malibus and Novas. I've always known they were great performers but am starting to think one would be a great idea next time I build up a car. I've also come to liking big blocks which I never really did before just due to a little ignorance and weight issues. The power some of you guys make with stock heads and mild cams is great!

David,
Think I already mentioned this to you but a friend of mine using an XE284 cam in a 383 and was having all sorts of idle and street drivability problems until he switched to a 650 speed demon. He only had 8-9hg of vacuum at idle in stick car. No report on track performance tho.

The only Chevelle downside is weight!!

No timeslips David? What kind of dyno?

What really bother me on the dyno was that a 4779 double pumper out performed the 3310VS by 30-40 TQ/HP. I don't have any idea how that happen.
Hopefully some carb experts can chime in here. both carbs had orginal jets & power valve.

Originally posted by Rapid Robert:
No timeslips David? No timeslips
I'm being held back by some parts that I send out to get chromed that I was ripped off, so now I have to find somebody to fabricate the parts again. graemlins/angry.gif
Here is the fellow Chevelle owner (73ChevelleSS454) who has ripped me off of parts and money $187.00:
http://www.chevelles.com/forum/ultimatebb.php/topic/35/2527.html

If you are after all out performance I'll take a double pumper everytime. Those numbers don't suprise me.

David,

As stated on the other boards, we would have recommended a 750 Mighty Demon on this combination. Installing a 4-hole carburetor spacer should help you out. Not knowing which 3310 carburetor you were dyno testing with, it's hard to say for certain, but since the data aquistion is showing that the 3310 is moving more fuel it would most likely have restricted the amount of air flowing through the carburetor, hence the difference in power. You have to look at the average numbers since those are what tell the story. You were looking at about 8 ft/lbs, 9 hp on the average. That is what's going to make the difference. Since the Demon you have is less restrictive than the other two carburetos you should see a noticable difference seat of the pants, or if you have the chance to re-dyno.