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Discussion Starter · #1 ·
I recently upgraded up to a 4v and installed a edelbrock carb and intake.
I have noticed that my gas milage went waaaaay down.

I have been told that I can install a clutch fan, and that will make a big difference.

Is there anything else I can do?
 

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The Edelbrock has smaller primaries than the secondaries. The primaries are probably as large as the primaries on a 2V carb.

Keep your foot out of the secondaries.

Have your new carb tuned by a pro.

Upgrade to electronic ignition.

For a warm SBF, a 600cfm carb is plenty, hope you didn't use a 750.

You have to expect swapping a 4V on will decrease your mileage. If it's too much a drop, consider swapping back, or swap on EFI.
 

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If you want to save on gas contact "Midlife". He has the abiltiy to "curse" your car were as you'll save on your wallet chucking out money for gas. :: Now I don't know this personally, but some things through the grape vine actually turn out to be true. :eek:
 

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Discussion Starter · #4 ·
Well a prp put it on...and I do have electronic igintion. I used the 500 cfm.
 

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67 coupe, 69 Sportsroof, 86 hatchback
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Actually unless you drive with your foot on the floor all the time you should have gained a couple of mpg's or at least stayed the same.
SWMBO drove her lightly modified 302 every day for about 4 years with a 2100. After I finally got around to swapping the intake and putting an Edelbrock 500 on she claims she has to fill the tank noticeably less often. We haven't measured the actual mileage gain, but I believe her as she's been driving the car the same way back and forth to work for so long.
I'd look into tuning the engine further, it may not be taking advantage of the new setup. It costs nothing to experiment with the engine timing. And though Edelbrocks are known to work fine "out of the box" it might could stand a little tweaking too. Beyond that, I recommend a set of headers and a free flowing exhaust. When I put them on my F150 I gained an overall 3 mpg and a noticeable power gain.
If you don't ever plan on dragracing your car, you might like an "economy" cam. They aren't good for higher rpms but do add to your mileage. A happy side effect is some added torque in the low to mid rpm range. This type of power can make a car a real kick to drive around town. Adding one to SWMBO's car is on my "to do" list. I'm definitely going to put one in my truck.
A clutch fan is beneficial in a variety of ways, but doubt you'll get noticeable results. You won't really get a lot out of any one bolt-on part. Your car will respond best to a carefully chosen package of performance parts chosen to work together.
 

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Have your driving habits changed? Typically, the primaries on a 4V carb are smaller than those on a 2V. Since a 2V only has 2, it needs them to be bigger when you go mashing the pedal. So, if your driving style hasn't changed, you *should* be getting better gas mileage. If not, then I would start looking at getting the carb tuned.

No offense, but if you are concerned about gas mileage, why would you switch to a setup that has the ability to use a lot of gas?
 

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Be happy, my car gets about 8 mpg around town. With the price of gas these days it spends a lot of time parked. :(
 
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