Is this a good deal? Will it do what I want? Carb/Intake

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dartnlo

dartnlo

Has Dart Fever
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Looking for an economy solution, both price and fuel, for my 1972 Dart 318.

Currently I have a 2 barrel setup. The 72 Carter is I think 375 CFM with 1.25" primary bore.

Edelbrock 2176 Performer Intake, 318-360 SB Mopar, Dual Plane, Dual Carb Flange | eBay

I found this intake on ebay and was wondering if it would be a decent choice. Also wondering what my carb options would be. Does the spread bore intake limit my carb choices to spread bore carbs? I was originally thinking about an Edelbrock 1406 performer and found one locally on CL.

Edelbrock 1406 carburetor

What do you think this would do to highway fuel economy? I'm currently averaging 15-16 mpg driving 55-70 MPH. Averaged over the last 500 highway miles. I know I will get worse in town as I will be tempted to get on it some but not much as I want this 108k mile 7.25" rear end last for awhile.

Also wondering if this intake will necessitate modifications to my stock coil mount.

I'm just thinking for under $350 this would be a good deal.

Thanks in advance for your expertise.
 
Murray said:
If you are concerned about gas mileage why would you change anything?
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Looking for less CFM/primary bore for the highway. I'm thinking the 600 CFM four barrel's primaries should be smaller than the two barrel at 375 CFM. Less air, less fuel. Is that not correct?
 
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dartnlo said:
Looking for less CFM/primary bore for the highway. I'm thinking the 600 CFM four barrel's primaries should be smaller than the two barrel at 375 CFM. Less air, less fuel. Is that not correct?
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Popular misnomer.
The engine will draw the volume of air it needs. The density of that air will vary with the throttle opening and air temperature.
Yes the 4 barrel's primary venturi and throttle openings are probably smaller than the 2 barrels. You could measure them to be sure.
But that alone only means that if everything else is the same, the air velocity in the smaller venturis will be higher.
Thermodynamics says the larger throttle opening will theoretically be more efficient.
In reality whether this results in more efficiency depends much more on other factors. Air/fuel ratio that more closely meets the engine needs and the most even distribution of fuel at part throttle depends on the boosters, the calibrations, the intake.

IMO the biggest factors for street driving will be:
a) properly heated intake with good part throttle fuel distribution.
b) good manifold vacuum
c) timing curves set for maximum fuel efficiency (power) and AFRs to match.

'72 timing curves and fuel mixtures were setup to reduce emmissions and to some extent that compromised engine efficiency.
For better fuel economy, I'd first look at timing. Something along the lines of what was used in '68, along with a slightly richer idle at lower idle speed. Yes slightly richer idle will be more efficient and produce more torque. Talking maybe 13 to 13.5:1 rather than 14.2:1.

Some carburetor designs like the T-quad and Quadrajet take advantage of the very small primaries for slight gain in signal, sometimes improved further with multiple boosters. Doing so often improved fuel distribution at low and part throttle and also let the manufacturers calibrate even closer. That said, not every spreadbore design does a good job. The Holley spreadbores have a reputation for being hit and miss and in any case the common ones didn't really take advantage of the small primaries.

If you want to play the eddy, that's fine. A four barrel will provide noticbley more power at the end of the quarter mile. :)
 
  • I wouldn't pay any more than 125 for the intake, including shipping. It's there now...
  • I wouldn't pay over 125 for a used 600 eddy. I just sold a practically brand new one for 125.
Now, a 318 2bbl with everything working right, in a A-body should get 20-22 on the highway. I've not had a problem getting that. If your not close, you might have a few valves not sealing. I'd start with getting it where it needs to be.
 
You want mileage, Sp2p eddy intake 500 cfm carb. You want even better mileage recurve your dizzy. If you want mileage from traffic light to light 3.23 if you want better highway 2.76. But that intake and carb should shoot you in the right direction I have a 318 mild cam 302 heads lb4d intake 600 edelbrock 3.55s get 17mpg car is not meant for mileage, this car is meant for chasing chubbys and ferds.
 
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I would hesitate on that manifold ! Someone tightened it down on the alignment pins on the front & rear rails, Its probably bent or cracked, very one I have seen with those marks have had cracks.
I would ask for a picture with a straight edge on the ends
 
Now that I looked at it it has a crack by the dist, if you look at the pictures you can see it on the inside and on the out side
 
very common intake.

can be had at swap meets for $75

same for a 500 or 600 Eddy AFB
 
Thanks everybody for the suggestions and insight! I'll continue searching with all this in mind.
 
Buy a rebuilt eddy at Oreilly’s or other auto parts stores. They are pretty cheap. A lot of times people are selling used carbs for a reason.
 
Put a good tuneup on what you already have. Tweak the distributor and the carburetor and you should be in the 20 to 25 mpg range.
My dad and I were always tweaking the 318s for mileage. 21-22 was an average. Our 78 Volare with 318 automatic used to get 26 and 27 on the interstate. That's was with the original carburetor and distributor and a lock up transmission.
Super tune it.
 
Jadaharabi said:
Put a good tuneup on what you already have. Tweak the distributor and the carburetor and you should be in the 20 to 25 mpg range.
My dad and I were always tweaking the 318s for mileage. 21-22 was an average. Our 78 Volare with 318 automatic used to get 26 and 27 on the interstate. That's was with the original carburetor and distributor and a lock up transmission.
Super tune it.
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That's milage on the Volare is impressive.
My folks got 21 mpg avg with our then brand new '69 Belvidere with 318 and torqueflite. NJ to Pensacola, with A/C on for some of it.
Only tweak was my folks had it set to use American High Test or Premium. In other words, the timing was slightly advanced and they used what would be the equivalent of 93 octane.
 
70 MPH and your NOT going to get good gas mileage, I have a honda 4 cyl for that
 
Every $75 or less Eddy carb I've bought at swap meets worked great either just bolting on or after a good cleaning.

Not a lot to them.

I do prefer to get one that smells like gas, so it's less likely to be gummed up hard from sitting.
 
69FBCuda said:
70 MPH and your NOT going to get good gas mileage, I have a honda 4 cyl for that
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True. The last trip I took was basically gas station, back to the same gas station with 98% highway miles and I kept it at 63 which is where I calculate 2000 rpm to be at with 2.75 gears. I had some headwind coming back and averaged 15.8 MPG over 150 miles. Pretty much what I get no matter what speed I go on the highway.

I'm working on my tune today. Also going to check compression to see if I have valve issues.
 
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