best "square flange" carb for millage?

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mod5v

mod5v

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Ok so I have been driving my duster to work every day. I live in a area that I can't park a car outside so unless I am willing to sell the duster {NOT!} I will have to keep driving it. I have a 60 mile round trip and need to optimize my millage.
Current configuration is
360+.030" 8.5-1 comp
"J" heads "hughes stage #2 ported (68cc cambers)
340 grind cam
wiend dualplane intake
650 holley dp
cheap headers-2 1/2" duals
msd dist +6al box 36deg total adv all in by 2000rpm
4sp w/2.76 open rear
255/60/15 rear tires
I think that the holley dp is just not a very good "millage" carb. I have adjusted the pump linkage so that they are less "sensitive" and am running as lean as I can but I still only get about 13mpg.
Now I know that the cam and heads are not helping the millage thing but for now untill I can get the room to put in the "magnum" based engine I want its what I have to work with.
I was thinking that a edelbrock "AVS" or "AFB" carb would be better for millage but not sure if it would make a lot of diffrence. Has anyone had experiance with just changing from a Holley to a diffrent carb and the effect it had on millage? Which one would be better for millage and yet be tunable for the amature like me? I can tune a holley for performance but never worried
about millage befor now. any help would be welcomed
Dan

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Ever thought about moving.

I wouldn't detune my car just because of mileage. Gas right now is $1.84 a gallon here in SC!

Holley is for performance and a Edlebrock is for gas mileage that's the way I look at it anyways. lol

So to answer your question get you a Edlebrock 500 cfm carb and try that for awhile. Keep in mind that they have 2 barrels that have more CFM.

But on the other hand you can make the carb what you want by changeing needles or jets.
 
Even with a DP you should be doing better than 13 highway with the 2.76 gears. But "Double Pumper" and "Gas Mileage" are generally mutually exclusive concepts.

Since that is a pretty mild combo (almost identical to the 74-76 360 4V) I wouldn't be to quick to de-tune it. I would try something like an Edelbrock 1406 and make sure your vacuum advance is tuned, working properly and connected to ported vacuum source. The vac advance is easily worth 2 MPG.
 
Knowing the cam is hurting the mileage problem, try some Rhodes lifters! I have used them before and they have worked excellent when I needed my "Hot Rod" for everyday useage. It really helped tame the cam down.

Any 600 cfm carb would do, but I like the Carters myself, alot.

Your probably not going to like this idea, but it is going to help in more ways than one. 1.88/1.60 valved 360 heads. Your build has absoultely no need for ported heads.

And I know your going to hate this suggestion. BUT;
For your mileage hunt, use stock 318 heads. It'll have loads of torque, hi velocity will be a real turn on for your engine.

OH, since it is a dual plane intake from Weiand, it's a spreadbore, try that type of carb for a edge in the mileage unt. It works. A minimal gain, but every little bit in the direction will help.
Electric choked T-Q. Hard to find.
Regular T-Q, no choke control unless it has a choke well.
Quadrajet. You can get them new from Edelbrock. A bit pricey, but new and very tunable with MoPar linkeage. (? on linkage?)
 
rumblefish360 said:
And I know your going to hate this suggestion. BUT;
For your mileage hunt, use stock 318 heads. It'll have loads of torque, hi velocity will be a real turn on for your engine.
Click to expand...


I have a 360 with the small valve (302) 318 heads. I love the torque and throttle response. Just to let you know that it does work well together.
 
Thanks. It never will stop amazing me how well that combo will torque up a 360. No one EVER believes you.
 
First the intake I have is for sq bore only. #7507 and I really don't have room for an adaptor. So square bore it is. I would have a TQ on it if it would bolt up. As for the build it's the way it is due to economics.
I had a 30 over block and the heads and intake and headers and carb and cam and crank and rods .. Wew!! from my previous oval track racing endevers. I was on a very limited budget so I got some 130$ sp pistons and hasting rings and used gaskets that I had laying around and put this motor togather. only "new" parts were the pistons,rings and bearings and gaskets. everything elses was recycled.
Then I moved and had to leave behind the rest of my 25 year collection of parts. So I have what I have and want to due the best I can with it.
I would really like to put a "magnum" topend on this motor as it would bump the comp up and give a lot better volocity to the mixture which should help millage but I would have to do it all in a weekend and I would also have to change the lifters (might as well change cam to) because I have no Idea if the liifters I have would oil the pushrods. I guess where I'm going with this is for now I would like to try a eddy carb to see if it would help while I get my living and economic life in order. I could get a carb off e-bay for 100$ or less and just was asking which one would be easyest to tune for millage.:read2:
 
Easiest to tune for mileage? Seeing there both the same (Edel.carbs) on the primarys and the secondarys are only really different via spring loaded door, I guess an edge could be found with the AVS style carb. You could wind up the spring a bit to prevent full secondary useage. A Holley could be very good as well, there secondarys normally do not open very quickly

I'd do the lifters and leave the cam alone. Those lifters are AMC styled and will oil magnum heads without issue.

Also, for a budget, leftover parts build up, good work. I know that deal. Living with it now. It aint preety sometimes, but that's todays hand from the dealer. It is what it is.
 
I have a 500 CFM Eddy carb that I more than likely never use. I took it off my 273 that I switched out to a 360 this year. The carb is fairly new and still have the orginal box. To be honest with you I would much rather see you get this carb because I know it works well and isn't like that junk on ebay. (IF) you think it will work on your 360.
 
I picked up 5 mpg with a Holley 670 Street Avenger over a Holley 3310 750.

I have a fairly hot 360 that I drive daily in the good weather and my commute is 48 round trip. On the back road commute I am getting 17-18 mpg and on the hiway I get 21-22 mpg.

I have an A833OD wit 3.55 gears and 255/60 tires which is close to the to standard 4spd with 2.76 gears. But I run magnum heads which are a fast burn design which is more efficient so you won't likely do as well but 20 mpg is not out of the question.
 
Another member sugested disconecting the secondaries and wireing them shut and that I should be able to reduce the jet size and that should help milage as much as a diffrent carb. I'm going to try it as it wont cost me anything to try.
Along these lines if you were to put a diffrent cam in this motor what would u pick for a milage cam in a low comp engine? I do have a set of 1.6-1 roller rockers and pushrods for a solid lifter I would have to get pushrods for hydrolic lifters if I went with these rockers and a "juice" cam. Thats the only reason I don't have them in right now. My heads and springs can handle a 0.600" lift cam no problem so I'm set there for anything.
 
I really don't know the whole situation but why not leave your Duster alone and do this:

A) Park the Duster at one of your family members house or close friends (anyone that wouldn't mind your car at their place that you can trust). Buy you a cheap 4-banger to put 60 miles a day on... not your classic Duster.That just sucks! I would never under any circumstances drive my cuda as a daily driver... I might for a little while if I had to but all year long in rain,hail,snow,blazing sun,people opening their doors on it etc...etc....nope not me. Also this will allow you to keep the motor a powerful beast because detuning it is really not why you got the car in the first place,(most of the time you more power not less) it will cut down the chance of someone plowing into the side of the Duster if you are involved in a wreck. I have experienced this first hand and have pictures to show it. Thank God I had classic car insurance on a 68 Dodge Charger.. a dumb *** driver T-boned the side of it and put me in the hospital. The parts for the old cars are getting harder and harder to find. You should be able to afford insurance on both cars. My 67 cuda insurance is $215 a year FULL COVERAGE with Hagertys. You might say "I can't afford it ... I have to keep driving it." I'll be glad to show you pictures of my wrecked Charger ... I was driving it every three weeks just to keep it running good not everyday when this happened. This might not make since to you but if you had been through what I have you would understand.

B) Or buy you a used 2bl 318 or /6 and install it in the Duster and take your chances.

If anything make sure you have full coverage classic car insurance. If it gets totaled then at least you want get blue book value.
 
rumblefish360 said:
Knowing the cam is hurting the mileage problem, try some Rhodes lifters! I have used them before and they have worked excellent when I needed my "Hot Rod" for everyday useage. It really helped tame the cam down.

Any 600 cfm carb would do, but I like the Carters myself, alot.

Your probably not going to like this idea, but it is going to help in more ways than one. 1.88/1.60 valved 360 heads. Your build has absoultely no need for ported heads.

And I know your going to hate this suggestion. BUT;
For your mileage hunt, use stock 318 heads. It'll have loads of torque, hi velocity will be a real turn on for your engine.

OH, since it is a dual plane intake from Weiand, it's a spreadbore, try that type of carb for a edge in the mileage unt. It works. A minimal gain, but every little bit in the direction will help.
Electric choked T-Q. Hard to find.
Regular T-Q, no choke control unless it has a choke well.
Quadrajet. You can get them new from Edelbrock. A bit pricey, but new and very tunable with MoPar linkeage. (? on linkage?)
Click to expand...

There is a company on eBay that has the 318 "302 swirl port" heads for $155.00 a piece. They come complete with a 3 angle valve job, new springs, valves, guides and seals. Shipping is only $25 bucks each.

Here's the link: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=370087754586&sspagename=STRK%3AMEWAX%3AIT&viewitem=
 
Well I'm new in this town and don't have anyone that I can store the car with. But I do have agreed value full coverage insurance.I really hate to drive this thing every day but untill I get some things worked out thats my situation. I do take the wifes car every time she dosen't need it so I actually drive the duster probably an average of 3 work days a week right now. The problem is that she is job hunting and when she gets one it will be back to 5 or 6 days a weak. Well it is what it is and I am as carefull as I can be and drive very defencively.
 
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