77 318 economy/performance mods

[black71]

picked up a 318 out of a 77 aspen to put into my duster...any suggestions for better performance and economy...i know these are pretty low compression motors but thats about it...any suggestions?

[Tonefiend]

How about an intake, 4bbl and headers. 

[spitnl]

Raising the compression should give you both.

[HP2]

As much compression as you can get away with, hot spark with as much timing lead as practical under cruise, lean out the mixture as much as practical.

[shadango]

Just to share 318 stats -

I believe my 318 is a 76 or 78.....

It has a Eddy 4 bbl  600 cfm carb, a performer manifold, Doug's headers and a hotter cam (no idea on the specs), big K&N filter, 360 "j" heads.

Stock ignition, initial timing is bumped up pretty high.....no vac advance. I do have better wires though.

2.76 gears

I get around 10-11 mpg around town.

What are you looking to get out of it?

My 5.9 (360) Durango and 5.2 (318) are stock and have MPFI and get about the same.

My wife can drive either of the two trucks and get 12-13 around town. Her foot is lighter.  LOL

[GoodysGotaCuda]

I don't really have any help as far as economy goes. My 318 pushed my Barracuda 13.6 sometime last year on 29.5" slicks. Don't too bad for a little boat anchor. milled 360 heads/cam/intake/exhaust. Pretty basic stuff.

[Moparal]

Install a 1bbl carb and add nitros oxide . You will have the best of both worlds for that 318

[NoMope Greg]

If it weren't for the cast pistons, that low-compression 318 is just begging for a blower of some sort.      

[HP2]

I'm running a small summit ground cam with as much compression as possible in my 440 in my truck. It routinely gets mileage in the low teens around town and the high teens on the highway. I've also set it up so my torque peak is the same as my highway cruise rpm. The torque peak in an engine is the volumetric efficiency point so anything you do to lower that to a practical rpm range that you drive in will help. Also, putting mroe squeeze in to the mix you have will increase the effiency of how the fuel in the mix is used, so as you get more power out of a given volume of air/fuel, which will allow you to reduce the throttle angle necessary to move the car which means you dump less gas in to it to move.

So I guess from a practical perspective, we should ask how far are you willing to go to get an increase? Is this a full blown rebuild or a simple bolt on exercise?

If it weren't for the cast pistons, that low-compression 318 is just begging for a blower of some sort. 

 Pressurize it anyway. If you explode the motor, so what. You simply get another 318. Its not like they are hard to find.

[Chryco Psycho]

a good cam swap & a set of the swirl 302 castings would make a big difference

[thesado]

I put a 340 cam in my 318.  Woke it up just enough to make it fun.  But I did loose a couple mpg too.  I'd recommend it.

[black71]

thanks guys, at this point just lookin at bolt on stuff right now..its just goin in a duster for the girl lookin for a little fun but enough economy that she can drive it everyday..

[Super Blue 72]

How about an intake, 4bbl and headers.

   Fairly quick and easy stuff to do.  Headers are a plus/minus thing, could go stock manifolds but have a nice dual system with mufflers that'll give a little rumble to make it sound cool. 

[Chryco Psycho]

I have found a 4 bbl intake & carb on a stock low compression 318 will notmake a significant difference in most cases

[Tonefiend]

I have found a 4 bbl intake & carb on a stock low compression 318 will notmake a significant difference in most cases

Mine sure is not much to write home about, but I never knew it before...