318 MAX fuel economy builds?

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gagembassett

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So I'm looking into buying a long-distance capable daily driver. I have my eyes on a Dodge Diplomat and Chrysler 5th Avenue. Both have 318s and I thought it may be of my own interest to buy one as a daily as they are things I can work on instead of things I would need to take to a shop. In the case that I buy one or the other I would like to build the 318 for high fuel economy, I'm talking like 20+ mpg if possible. Anyone done this? Any input? Etc. Let's coffee-table talk daily stuff instead of high horsepower for once.
 
So I'm looking into buying a long-distance capable daily driver. I have my eyes on a Dodge Diplomat and Chrysler 5th Avenue. Both have 318s and I thought it may be of my own interest to buy one as a daily as they are things I can work on instead of things I would need to take to a shop. In the case that I buy one or the other I would like to build the 318 for high fuel economy, I'm talking like 20+ mpg if possible. Anyone done this? Any input? Etc. Let's coffee-table talk daily stuff instead of high horsepower for once.
Probably get 20+ out of one of those. Most of those had a roller cam, the #302 heads, and a lock up 904 transmission with a low rear gear (like 2.87 or whatever) Heck, my 70 318 2 barrel with a standard 904 and a 3.23 gear gets a steady 19 on the highway.
 
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If it has the original "Lean Burn" ignition get rid of that. Just a Mopar electronic or even a Pertronix in a old point type distributor.
 
Use a small [ 800 cfm ] TQ carb. To resist the temptation to use the secondaries, disconnect the link connecting the pri to sec. The extra booster ring in the TQ primaries provides exceptional fuel metering & atomisation, a must for good economy.
 
I think that goal is reasonable and achievable. I had a clapped out dippy that got high teens and was a fender flapping refugee from the junkyard.

while all the generalities are of a concern (rear end gear, transmission operation, in good tune/running properly) I think that there is a whole other level that could be unlocked for little gains that may reap rewards not only in mileage but in reliability, a touch of performance and ease of operation.

little things like a sanden compressor for the AC, an electric fan, a denso alternator are all lighter and would free up power. lighter aftermarket rims free up horsepower, taller tires lower RPM.

a 2bbl vs a 4bbl would be an interesting experiment, as would 318 v 360. I'm of a mind that a well sorted 4bbl with tight 2ndaries would probably fare just as well as a 2bbl in the city if you kept your foot out of it.
 
How about a Cordoba 2.54 rear in a Dippy? And an RV cam and an SP2P intake with a Holley 450 economaster carb? Talk about a Weezer!
 
So I'm looking into buying a long-distance capable daily driver. I have my eyes on a Dodge Diplomat and Chrysler 5th Avenue. Both have 318s and I thought it may be of my own interest to buy one as a daily as they are things I can work on instead of things I would need to take to a shop. In the case that I buy one or the other I would like to build the 318 for high fuel economy, I'm talking like 20+ mpg if possible. Anyone done this? Any input? Etc. Let's coffee-table talk daily stuff instead of high horsepower for once.
My parents had a 1985 5th Avenue that they bought new and before they took delivery of their new car my dad had the dealership install Bosch platinum plugs and with premium fuel dad said that it got 30mpg on the highway. It had the lean burn system and a 904 transmission, no overdrive. I've heard of others getting in the mid 20's with the 5th Avenue and they are as aerodynamic as a shoe box.
 
So I'm looking into buying a long-distance capable daily driver. I have my eyes on a Dodge Diplomat and Chrysler 5th Avenue. Both have 318s and I thought it may be of my own interest to buy one as a daily as they are things I can work on instead of things I would need to take to a shop. In the case that I buy one or the other I would like to build the 318 for high fuel economy, I'm talking like 20+ mpg if possible. Anyone done this? Any input? Etc. Let's coffee-table talk daily stuff instead of high hoepower for once

So I'm looking into buying a long-distance capable daily driver. I have my eyes on a Dodge Diplomat and Chrysler 5th Avenue. Both have 318s and I thought it may be of my own interest to buy one as a daily as they are things I can work on instead of things I would need to take to a shop. In the case that I buy one or the other I would like to build the 318 for high fuel economy, I'm talking like 20+ mpg if possible. Anyone done this? Any input? Etc. Let's coffee-table talk daily stuff instead of high horsepower for once.
Check with 318willrun, he has a ton of knowledge and experience with the teener. I'm sure that he would help you with your goal.
 
I would use an Edelbrock SP2P intake and an Edelbrock 500 CFM AVS2 for induction.
 
How about a Cordoba 2.54 rear in a Dippy? And an RV cam and an SP2P intake with a Holley 450 economaster carb? Talk about a Weezer!

I was *just* gonna say a holley economaster! but I was gonna go performer intake in that it would probably be easier to find...

but some freeway flyers out back for sure. wouldn't be totally flat footed in the city with a 999 or 904 with that deeper 1st gear.
 
So I'm looking into buying a long-distance capable daily driver. I have my eyes on a Dodge Diplomat and Chrysler 5th Avenue. Both have 318s and I thought it may be of my own interest to buy one as a daily as they are things I can work on instead of things I would need to take to a shop. In the case that I buy one or the other I would like to build the 318 for high fuel economy, I'm talking like 20+ mpg if possible. Anyone done this? Any input? Etc. Let's coffee-table talk daily stuff instead of high horsepower for once.
Other than basic tuning it's hard to recoup money spent on mpg gain's, for one it's takes a certain amount of horsepower to move your car down the road which takes a narrow amount if fuel. It's hard to make gain's on a well tuned and setup car. A 10% improvement on a 15-20 mpg car is only 1.5-2 mpg gain. You'd have to burn a lot of fuel a year and keep cost of upgrades to a minimum generally to be economical. If you start spending $1000's and don't drive much could take a decade to recoup. Not saying not to but figure it out first could be just cheaper to dump it in the tank.
 
I've been reading up on intake manifolds and a lot of guys say that the edelbrock performer isn't much of then the factory intake, is the weiand action plus any better?
 
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