318 la upgrade for gas milage

[flyinmike]

i have a 1964 dodge 440 car that i plan on putting a la block 318 in.my question is what head to put on,i have the stock 318,a 340 ,and 360 swirl port. i want it to be a summer time daily driver, i am strictly shooting for gas milage. from what i've read the swirl port are the ones i should use. i also have a 360 engine but not as good on gas.any help on what to do to the 318 for gas milage would he appreciated.machinning costs are not an issue as i have access to a machine shop.

 

[RustyRatRod]

The 360 might be better on gas than you think in that big old car.

 

[YY1]

Not to start trouble, but I believe the 63-65's are the lightest Bs, followed by the 66/67, and they just kept getting heavier...

 

[RustyRatRod]

Not to start trouble, but I believe the 63-65's are the lightest Bs, followed by the 66/67, and they just kept getting heavier...

No trouble here. I get what you're sayin, but keep in mind I'm an A body guy come over to the dark side. So when I say big old car, I'm usin an A body for comparo. lol

 

[flyinmike]

i thought they were a boat also,but surprized at how much they weigh

 

[Cranky]

How much does it weigh? My 66 Belvedere was 3370 with /6, auto and ac, with no ps or brakes. How and where you drive will all affect mileage. A highway rear gear in town won't get the highest numbers just like a low rear ratio won't do so well out on the road. An OD transmission coupled to a rear gear that is kinda low (say like a 3.91) is usually a good way and gives you great response in town and still gives you a decent cruise rpm on the higher. A longer stroke engine can usually deal with a higher gear since they can run a lower rpm and still have the torque to pull vs a small engine's torque band being higher in the rpm range. Higher compression can also improve mileage and power output but your cam needs to be matched to whatever combo you use.

 

[kb67mopar]

I think the swirl port head had a larger combustion chamber size. Realistically for a 318 any of your head choices are good but make sure the compression ratio will be ok. Putting a large open chamber head on a stock 318 tends to get you below 8:1 with the X or J heads. now if the 318 is younger (late 70's) I think they put a taller piston in to accommodate the open chamber. You will have to do the homework because its been a while since I had read about this stuff. Basically my choice would be a closed port 360 head with a cam that won't bleed off any compression.

Or just put a 318 magnum out of a newer truck in it, should run well and get good gas mileage out of the box.

Oh and I think my 67 2dr post listed a shipping weight of 3180?

 

[RustyRatRod]

Honestly and with all due respect, if you are trying to get an old V8 Mopar (especially a B body) to get "good" mileage, maybe you picked the wrong hobby. I think the absolute max would be close to 20 and that would be with a stiflingly small carburetor and really lame highway gears. How fun is that gonna be to drive? A big block in that same car with a loose converter and 4.10 gears could see 12 to 13 if driven conservatively. Fuel miser type mileage is something the factory engineers never designed into these cars, so it will be extremely hard to design it in after the fact.

 

[flyinmike]

from what i've read if i got it right is the 360 swirl port heads will raise compression.it's a 69 318 and if i use the stock heads i know the seats will have to be done.decking the block and milling the heads will be done.what does a closed port 360 head come in and how can i identify it.i guess i need to research this to see what piston to use.the weight of my car from the facory is around 3200 lbs.

 

[RustyRatRod]

That's incorrect. It will drastically lower compression. The 360 swirl port head is the 308 casting. It is an open chamber design and on a 318, that will put compression in the crapper.

The heads you probably want are the 302 castings. They are the 318 swirl port heads. They have heart shaped closed chambers and will raise compression over the open chambered heads.

from what i've read if i got it right is the 360 swirl port heads will raise compression.it's a 69 318 and if i use the stock heads i know the seats will have to be done.decking the block and milling the heads will be done.what does a closed port 360 head come in and how can i identify it.i guess i need to research this to see what piston to use.the weight of my car from the facory is around 3200 lbs.

 

[Cranky]

from what i've read if i got it right is the 360 swirl port heads will raise compression.it's a 69 318 and if i use the stock heads i know the seats will have to be done.decking the block and milling the heads will be done.what does a closed port 360 head come in and how can i identify it.i guess i need to research this to see what piston to use.the weight of my car from the facory is around 3200 lbs.

Weight listed on the title for my 66 2dr post Belvedere is 3200 but it still tipped the scales at 3370. I've never had a car that weighed what the title said...

 

[kb67mopar]

Weight listed on the title for my 66 2dr post Belvedere is 3200 but it still tipped the scales at 3370. I've never had a car that weighed what the title said...

They also didn't seem to list a difference in weight between /6 and big block that i recall... so definitely a margin of error there.

And getting decent mileage from a 3300 lb car is not that hard. Just need the right combination of parts. Now being, quick and fun to drive will be another story. Though getting 12 mpg is a waste of time and I would sell my coronet if it ends up only getting that. You shouldn't have to be rich to enjoy the hobby.

I am going late model hemi for this reason, should be up around 21-24 mpg highway according to what I have read.

Heck one of my co-workers has a new challenger with the 5.7 and six speed manual, he averages mid 20's to nearly 30 hwy.