Demon carb tip

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Mar 20, 2002 | 01:07 PM

74vetteman

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From: Calgary

Demon carb tip

When I was dynoing my 406, the dyno operator showed me a interesting tip. My 750 Demon came with a choke tower (although with no choke) with a hole on either side for the choke butterfly rod. By putting black electrical tape on the outside of the choke tower, and covering those holes, my 406 made 8 hp more! Seems like those holes create turbulance which affects the airflow through the carb. I will have to think of a more permanent solution though.

Mar 20, 2002 | 01:34 PM

Lt1er

Drifting

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From: Reno nevada

Re: Demon carb tip (74vetteman)

Was that with an air cleaner in place?

Mar 20, 2002 | 03:25 PM

74vetteman

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Re: Demon carb tip (Lt1er)

There was no aircleaner in place.

Mar 20, 2002 | 06:02 PM

88WHITE VETTE

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From: Park Ridge IL

Re: Demon carb tip (74vetteman)

On Holley, you can just use small screw with washers on each side (big enough to cover the hole) and use locktite to prevent from coming off. At least that's what I did, and I am not sure if it will work on Demon.

That's a BIG gain, are you sure that was the only thing changed on that pull?
Ziggy.

[Modified by 88WHITE VETTE, 5:02 PM 3/20/2002]

Mar 20, 2002 | 07:47 PM

74vetteman

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From: Calgary

Re: Demon carb tip (88WHITE VETTE)

We only changed one setting per dyno pull.

Mar 20, 2002 | 09:13 PM

gkull

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From: Reno Nevada

2024 C3 of the Year Finalist- Modified

Re: Demon carb tip (74vetteman)

How is your Speed Demon jetted. I have settled in on 75 front 82 rear and 6.5 power valves drilled out squirters and .125 inch holes drilled in each pri. throttle blade.

Could you also give me the low down on all your engine parts?

[Modified by gkull, 7:25 PM 3/20/2002]

Mar 21, 2002 | 01:31 PM

74vetteman

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From: Calgary

Re: Demon carb tip (gkull)

The only changes to the 750 Demon were jetting changes. Best overall performance was 2 sizes over factory settings. I believe we ended up with 82 primary and 89 secondary (I'm out of town right now and don't have my info in front of me). We are approx. 3600 ft above sea level.

Engine parts:

Champ oil pan with trap door baffle and windage screen (5 quart)
High pressure high volume oil pump
Factory 2 bolt main caps (rear cap oil passage ported)
ARP main studs
Scat cast steel crank for 6 inch rods (internally balanced)
Eagle 6 inch H-beam rods
SRP forged pistons (flat tops with full floating pins)
Block decked .020, line bored, 0.030 over
Crane roller cam with 224 intake and 230 exhaust duration (all crane valve train)
1.6 roller rockers
AFR 210 race ready porting heads (76 cc combustion chambers) ~10.3-1 compression
Weiand 7530 team g single plane intake (we also used a .5" spacer) More power could have been made with a thicker spacer but I have limited hood clearance.
Demon 750 double pumper
Hooker super comp headers (1 3/4 primaries and 3" collectors)

[Modified by 74vetteman, 11:34 AM 3/21/2002]

[Modified by 74vetteman, 10:31 PM 3/28/2002]

Mar 28, 2002 | 01:16 PM

Keith1979

Intermediate

Joined: Mar 2002

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From: Wichita KS

Re: Demon carb tip (74vetteman)

Nice setup 74vetteman, my setup is similar to that except a bit bigger cam and afr 190s and 383. Im glad to see you are making that much power, i should be close to that hopefully. I havent got it in my car yet, im still waiting for my block and then ill need to assemble it.