Well, there are those low rolling resistance tires--they might help.

Depending on how crazy you want to get you can charge your battery at home and disable the alternator--it will save you gas, and the equivalent cost for electricity is much less than gasoline is right now. You best have a short round trip however. Helps if you don't use your lights, radio, etc.

Really, all of these tweaks can only get you a few (probably less than 5) mpg more. If you want better than perhaps a Geo Metro is what you really want. The Slant Six is what it is--especially in a van. if you had a Dart or something smaller and lighter you could do better on the mpg.

I wonder what the payback would be on the tires if they got you maybe 2 mpg more. Probably a long time if you have good tires, if your tires are about done the pay back is inherent in the new tire buy. I recall Pirelli making these at one times, the P8 or something...

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Slanted D150

One of my best physics professors used to call this sort of thought exercise a "Fermi problem". They were good for getting us to think logically and accurately about the order of magnitude of any given effect, phenomenon, or change.

It would be hard to get a 2 mpg by swapping the tires.

It would be even harder to get 5 mpg improvement out of any set of mods to this vehicle; that would be a giant 28% improvement, which probably is not very realistic to expect.

But if there's a problem with the baseline state of tune or repair (though at 18mpg it doesn't sound like it) then perhaps such an improvement is possible.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Considering the van was getting about 3 MPG before I tuned it up for my brother the last time, I think he is happy with how it is doing. I don't think much more can be gotten out of this motor/body combination. I was just looking for any ideas I hadn't tried yet.

Thanks again!

Reed,

I approached Doc about what to do for torque and mileage. I am at the 30,000 mile point on the build and it is still going up. I am a slow methodical tuner taking lots of notes each step of the way.

To get more torque out of the engine, you could install the 40" long Hooker 3X2 headers with 12" collectors. Summit Racing sells them. This was a mod that along with the Super Six the Chrysler engineer Pete Hagenbuch urged us to do and said it would gain allot of torque as well as mileage. He was trying to get me to do this on my Swinger however, I am still at the point of fine tuning the 1920 Holley thanks to Juan's help "The Argentina Slant Sixer". Apparently on all my 1920 Holley's the low speed idle bleeds are plugged. I have opened the idle air bleed up which has activated the emulsion circuit which has benefited in some nice mileage gains by jetting richer. I am in the process of documenting results with larger jets, one step at a time. Eventually I want to go with a Weiand four barrel manifold and run a two barrel.

I am running the stock 1980 aluminum one barrel manifold with no porting. It warms up quicker over the cast iron for better mileage. When running headers you could run water heat under it at the stove box. I am still using the stock exhaust manifold, however, it has been ported out quite a bit at each port and at the outlet The exhaust ports on my head have not been overly ported but the intake has been opened up to match the gasket along with the bowl porting. This seems to produce some good power along with the taller lift cam which is also advanced 4 degrees. I am getting a little more torque with another thought Dr. Dodge shared with me on the valve lash. For a little more seat time I am at .012 and .022 which also helps with mileage and power.

Since the SL6 has alot of windage and most folks don't run trays or scrapers, I am trying 0-30W Mobil One with a Wix 1806 stand pipe filter which has also has netted another half mile to the gallon increase in mileage. It starts up immediately, is much quieter, runs cooler, has 50 pounds pressure and will go from 60 to 90 in a heart beat.

One of my mileage problems is that now that the engine has allot more power, it is tempting to drive it harder and have some fun.
I went through 3 rear ends in 5 years, so I custom built a 8.75 rear end with 2.76 posi to slow me down but I can still break the rear end loose at a light like it was still running a 3.23.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Reed,FYI.Scale wt on my vans,79 4x4 3843#,80 2792#,83 3316#,all are shortys.The two newer ones are /6 4spds and the scale wt is what Wa.Dept of licensing charges our tax on.I'm sure they are abit heavier then that but still not as heavy as most people assume a van is.I personally wouldn't pump up the tires to 45# as more than likely that will just wear out the center tread.If the van in question has wide tire/wheel combo go back to a narrower tire/wheel,wide looks cool but its a rolling resistance killer.18 mpg is good,that's about 10 more than my 360 4x4 is getting,does your brother want to trade?

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83 B-150 slant 6,4 speed. 79 B-300 360 pathfinder 4x4. 74 W-300 318 4x4 git-r-done 80 B-100 sl6,4speed

WOW! Thanks for the info guys!

I am pretty sure my brother doesn't want the expense of buying a header, and I think I will stick with the cast iron two barrel for now.

The van is running a set of 15x7 factory steel wheels. They are the "Street Van" or "Little Red Express" chromed wheels:



Ted: If the van were mine I would definitely try the header and the one barrel, but since it is my brother's and he is getting the labor/parts for free I will leave it as is. I always did like the Holley 1920 carb though!

I will set the lash as per Doc's recommendations too.

Are ya sure? If the engine in that '83 is original, it's got hydraulic lifters which have no lash to adjust.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

The engine is a rebuilt 1976 forged crank motor that came out of a 76 Volare I used to own. The original motor was hydraulic and was also toast.

mmMMMMmmm...hydraulic toast....

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I will also vote for Dutra Duals here. Even if you just have them going into one pipe (like me) it's worth it.
I would try to lose a little weight in that big 'ol van. An Offy aluminum intake, even though this is not free. Did any vans come with manual steering? I know, manual steering in a van would be a little inconvenient.
18mpg already isn't bad!

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"Ja, Ich fahre ein altes auto."
'78 Volare 225
'67 Charger 318

I thought about dual exhaust, but the AIR pump gets in the way of the front manifold, so it isn't possible.

Reed,another fyi,my 83 should be fairly much same same as your brothers.I've got clifford shortys on mine and IF the air pump was still there it wouldn't be a problem.Mine had a air tube that dumped into exhaust pipe up stream of the cat,so I'm thinking it could be replumbed if wanted or needed.Not sure on Docs duals but air pump should still clear? Both my /vans didn't come with air pumps/cats and such or were missing pieces,belt gone etc.I've got a pump for the 83 figured if some "Big Brother"ever got pissy about it could rig something up.If your bro ever wants to spend the money on headers/duals I don't think the air pump is an issue

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83 B-150 slant 6,4 speed. 79 B-300 360 pathfinder 4x4. 74 W-300 318 4x4 git-r-done 80 B-100 sl6,4speed

Thanks, I'll keep that in mind.

Reed,

Since you live up here, your safe, toss the pump and go with the Duals.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Actually, I had to add the pump to get the van to pass emissions. Back when i first tuned the van up it has a single barrel and no emissiosn equipment. It had horrible emissions and wouldn't pass the test. So I put on a two barrel, added the high-flow cat, and cobbled together the air injection system. It passes great now and it went from 3 mpg to 18. I figure I will leave it be for now since the van already has a 2.5 inch exhaust all the way back.