carb questions

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Jan 2, 2009 | 11:00 AM

$Simpleman76

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carb questions

i have a 351c 2v heads installed in my 78 ford f150 4x4 and was wondering about the carburetor I have installed an edelbrock 600 performer but I came across an autolite 4100 with the 1.08 venturis and was wondering if i would get better fuel economy and the same performance out of the 4100 as with the edelbrock just hoping someone can give me some insight it is my understanding because of what I have read that the 4100 is one of the best carburetors ever made even better than todays carburetors, am I wrong in thinking that. I have tried to build the truck as bulletproof as possible but I do plan on driving it a lot, the engine has a 280 roller cam and roller tip rockers with exhaust manifolds instead of headers, I am just not that good at matching carbs to engines so if anyone has any insight I would appreciate it thanks

Jan 5, 2009 | 05:41 PM

wyazel1

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Im not an expert, but i think thats a pretty big cam, what kind of compression are you running? I am running the Edelbrock 1411 750cfm on my 400 with 9.5:1 and a XE262H cam. I had the edel 1406 on my stock 400 before this build and it was great but you might need the 750 with that big cam. Someone more knowledgeable will be along shortly.

Jan 6, 2009 | 05:37 PM

Mud Rat

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From: Eastern Ohio

A 280 cam is way too big to run stock exhaust manifolds. Throw some headers on it and run at least a 650 carb.

Jan 7, 2009 | 02:33 AM

grclark351

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From: chicago burbs

the 1.08" 4100 is said to flow 480 cfm. is it worth $xx to find out? only way to know is to try... you could surely make more power with more carb but it doesn't sound like that's what you're after. i agree that you're choking the potential of the cam with manifolds, small(1 1/2"- 5/8") headers might help loosen up some power and improve efficiency.

what are you running for gears and tires? auto or stick? 351M or 400?

Jan 7, 2009 | 12:47 PM

MBDiagMan

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Joined: Dec 2004

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From: NE Texas

The only way that the carb change would buy you any significant fuel mileage would be if your old carb has something wrong with it or the 4100 happens to have a tune better matched to your engine. The latter is VERY unlikely.

Fuel mileage is determined chiefly by vehicle weight, frontal area, aerodynamics and driving style. The first three factors in the list are against you, so driving style is the only control you really have over the situation.

Unless there is something wrong with your current carb, you can experiment with carbs until you're blue in the face and if you were to find an extra 5% in fuel economy it would be close to a miracle.

Jan 8, 2009 | 02:13 PM

fordeverpower

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From: iowa

The autolite 4100 is special, it is rated at 480 but has been tested to flow 440cfm. The small bores and annular boosters would have great throttle response and fuel economy. The bigger 1.12 model is rated at 600cfm but has been tested at 520-525cfm. As for your cam, i would look at a holley carb around 600cfm and headers as other recommend. I bought a new 600cfm edelbrock before and didn't like it, and i got a holley 670 street avenger.

I have a modified 4100 on a hobby stock car making around 380hp. The venturi are opened up and many other mods