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Discussion Starter #1
Hey guys. Im in the market for a new carb for my 351. The po built the motor so I dont know the specs but it has 4v iron heads and intake, hooker long tubes, a moderate cam, mallory dist, mallory 140 fuel pump, msd box with blaster coil and I currently have what I believe to be a Demon 750 double pumper mechanical secondaries no choke with a 1 inch spacer. Mated to the motor is a T-5 trans with 3.55 gears/detroit locker in the 9 inch.
My current carb leaks at all the throttle shafts and I'm thinking about a new carb. Any reccomendations?? This is a street car but I am a spirted driver and will take it to the track once I build a stronger trans.
 

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Holley 750 dp should do the trick, depending on your exact engine configuration.

I'd leave the spacer on and just swap Holley for Demon, same advertised size.
 

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Discussion Starter #3
My demon is a four corner adjustment carb, whats the benifit over the standard primary and secondary single adjustment?
 

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Single plane intakes benefit from single secondary adjustment by making mixture adjustment simpler. Dual planes or really twitchy performance engines benefit from four corner idle due to the nature of the intake tract or the engine's behaviors (high idle speeds, one side runs leaner than the other...)

Holley makes a 750 DP with 4 corner idle, if it's something you want or need.
There are also Demon carbs still around that you can pick up on the cheap. I found a couple of deals in the garage sale at Speedway Motors.
 

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Discussion Starter #5
I figured out for sure what I have and its a Speed Demon 750 Mech secondaries. I wonder if there is a rebuild kit to fix my throttle shaft seepage
 

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I picked up a custom built Quick Fuel 750 carb for under 600 bucks. It is a really nice carb, and runs much better than the Holley I had. Billet metering blocks and base plate, 4 corner idle, smoothed main body with no choke. I was told that they actually flow close to 850 or 900, and in high speed circle track cars, can flow near 1000. I know I am happy with it, and you can still use standard Holley gaskets and most parts.
 

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Not yet. I sent the carb back yesterday because of a leak. He said it has been 2 years since he has had one come back but thats my luck. I think the issue is the alternator, just havent had time to mess with it yet.
 
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