318 or 360?

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dave ellis

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I want to put together an a body to leave North at our Summer Place in Wyoming. It will be used in the Foothills and the Rockies themselves. If I build a motor for good low-end and mid-range would would a 318 do the job or would it be worth moving up to a 360 and putting up with less mileage
 
I had a 70 Challenger S/E with a 318 that had plenty of power.

CDCA6062-5B9B-4B5D-859D-B609125912DA.jpeg
 
I grew up in the mountains of Colorado, and had both a 318 and 360 in my Barracuda....360 all the way....you need all the torque you can get (and they cost the same to build).
 
If you are going to spend the money do up a 360 easy hp and torque
I agree. I have a 318 that I overhauled almost 20 years ago, it was a temporary engine untill I had my 340 squared away. I dont recall doing any dumping of money into it except bearings,gaskets,cam, edelbrock intake which I then swapped the intake to the 340. I seem to recall it was a little over 500 bcuks dumped into it at the time and I dont think I counted the intake on that as I felt the intake was getting moved to the 340...the intake may have been another 250-300 bucks in 2003...
 
What kind of A body are you building (gearing, transmission, rear tie diameter, weight, etc.) and WHAT IS THE BUDGET? Not only do I say 360, but if making up for a loss of atmosphere, I'm a big proponent for a 4 inch crank.
 
If you are spending the $$ for a rebuild, yes 360 makes some sense. Or get a magnum 5.9 that needs no boring and still spend dollars.
If you find a good running engine worth the $ I would not hesitate for the 318. Lets say there is a difference between an early higher compression 318 and it smogger brother.
Just like gears, long legged 2:94 vs 3:55 Makes a difference.
 
Build it like a truck engine, good quench, lower compression (8.5: to 9:1), small cam and if you can add displacement. Small bore of the 318 might lend its self to better detonation control with a head that has a decent chamber.
 
Remember that the 360 and 5.9 Magnum were originally designed as truck engines. So was the Viper 8.4 ltr. and 5.7 Gen III Hemi's.
Low end torque. All externals accessories/brackets (except pan) are bolt ons if you already have a 318.
 
IMO, for cruising around a 5.2 is plenty good enough. It moved my 5000lb 98 Dakota 4x4 without issue and should be pretty spunky in a car 1300 lbs lighter. If budget is an issue, I'd just pick up the best looking, lowest mileage running 5.2 or 5.9 magnum engine out of a wrecked truck, put a Sniper and intake on it and call it good. While it's out you could put a little hotter cam and maybe valve springs in if you were so inclined.
 
I have a 360 at the machinists right now, and I am keeping it stock stroke, internal balanced with a new cast Scat crank. The 3.580" cost the same as the 4.000" crank. I plan to rev the **** out of it with 4.10 gearing.

YOU may have different plans than me, so your requirements will be different. I am shooting for high 11's at sea level, or whatever the hell t is here at Sears Point.

What do you plan to do?
Grocery and kid hauling duty?
Friday night cruise and racing in quiet Industrial areas?
Car shows and asshat judges gigging you for not having the appropriate amount of overspray on the e brake cable?
1/8th or 1/4 mile or Bonneville Salt Flats?

Pick your cam and gears based on planned use, then build your engine around that...

Most importantly, post up pictures.

And remember, bench seat and column shifter means that your girl can snuggle up with you, especially when it's cold and you "accidentally" leave the passenger side vent open a crack. I ain't telling you to do that, but I would understand.
 
I want to put together an a body to leave North at our Summer Place in Wyoming. It will be used in the Foothills and the Rockies themselves. If I build a motor for good low-end and mid-range would would a 318 do the job or would it be worth moving up to a 360 and putting up with less mileage


Either one will work and can be built for decent mileage...

My dad had a stock 76 Charger 2 bbl that got 20 MPG, so a 360 can get good economy if built right...
 
Either one will work and can be built for decent mileage...

My dad had a stock 76 Charger 2 bbl that got 20 MPG, so a 360 can get good economy if built right...
What did it have for gears? Tall tires?
 
A 318 is a very capable engine but there's no reason to build one over a 360 other than if you want to.
If built to the same power level I highly doubt any mpg difference between the two.

Or said another way the only thing wrong with 318's when it comes to performance is Mopar also built 360's and there plentiful.
 
What did it have for gears? Tall tires?


Larry Shephard said that the best camshaft for fuel economy is the stock 360 2 bbl cam...

I have a few of them waiting for an economy project...

There were a couple versions of the 360 2 bbl cam, but they are very close in specs, slightly different...
 
Larry Shephard said that the best camshaft for fuel economy is the stock 360 2 bbl cam...

I have a few of them waiting for an economy project...

There were a couple versions of the 360 2 bbl cam, but they are very close in specs, slightly different...


Ok now, pay attention folks... I found my camshaft spreadsheet...

The 71-74 360 2 bbl cam had 252/256 duration and .410/.412 lift...

In 75 they switched to 252/252 duration and .410/.410 lift....


Here's the difference according to Desktop Dyno 5 with a 318 and 9.0 compression:

71-74 360 cam:

318 9 comp 71-74 360 cam.JPG


75 360 cam:

318 9 comp75 360 cam.JPG


The 75 cam has 1 more horsepower and 3-4 more torque up to 3500 RPM then the 71-74 cam has 2 more horsepower and 3 more torque above 4000 RPM....
 
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Ok now, pay attention folks... I found my camshaft spreadsheet...

The 71-74 360 2 bbl cam had 252/256 duration and .410/.412 lift...

In 75 they switched to 252/252 duration and .410/.410 lift....


Here's the difference according to Desktop Dyno 5 with a 318 and 9.0 compression:

71-74 360 cam:

View attachment 1715799366

75 360 cam:

View attachment 1715799367

The 75 cam has 1 more horsepower and 3-4 more torque up to 3500 RPM then the 71-74 cam has 2 more horsepower and 3 more torque above 4000 RPM....
Early cam for the win!
 
I wonder how to translate that cam 2 one that will burn 87 pump . Maybe with about 8.4 to 1 mechanical compression?
 
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As proof of that I think your bomb cycle first run video is appropriate for this thread.
in fairness, the 318 had a very low stall behind it. But sure, the 360 makes more torque, the factory specs will show that.
 
360/(518)727rh auto or 3sp man with the OD with a 2.73 peg leg diff and 15in tires:thumbsup:
 
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