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Old 12-26-2004, 11:19 AM
DTL504 DTL504 is offline
84 Z28 Convertible
 
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Carb comparison Demon vs Holley

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
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