Rebuilding the 318... or going 360?

[BDL]

Did it have those round rubber thingys on it?...uhh... oh yeah, tires.

It did, it did! You saw it too?!?

 

[brad 66]

so how much hp can you add t o 318 with just cam , or cam and heads to 1976 318 .it runs good and I am not looking to go real fast . would just like a little bottom end with out going big block . have that in other car

 

[BDL]

so how much hp can you add t o 318 with just cam , or cam and heads to 1976 318 .it runs good and I am not looking to go real fast . would just like a little bottom end with out going big block . have that in other car

"How much HP... from a 318?" Really is an age-old question. Here's the thing... You can get a ton of HP out of, what many people consider a "throw-away" motor, the 318. You can just cam it. You can cam and head it. You can cam and intake it. You can cam, intake and head it. You can cam, intake, head and bore it. You can cam, intake, head, bore and stroke it. ...you get the idea. There are full discussions on the easiest way to get a little more HP out of it. As has been pointed out on this discussion, keep in mind that an engine with larger displacement will always give more potential for power. So, the 360 will give more power than the 318 and so on.

How much HP? Well... How much $ do you want to throw at it? What are the best heads to get? What is the best cam to get? You can see the line of questions. Unfortunately, there is no single answer to the question of "how much HP can I get?" That would be a good question for Hot Rod Engine Masters to tackle though!

 

[moper]

You will never get a big block torque feel from a 318. However parts can be added to gain torque low down, and you can gear the car to make the most of the power made. I would not replace the heads myself. Not if you just want a little more snap. Cam, intake, headers, and ignition and you'll be fine.

 

[rumblefish360]

Lol... I was trying to make a point to the guy who started the thread. I am well aware that an engine with a larger displacement will have more potential for making power (both h.p. and tq.). But the thread starter was saying the difference between a 318 amd 360 wasn't worth the swap. I was pointing out the negligible difference could be because the 318 may have had a hotter can than the 360. Am I new at this? Yup... just saw my first car last week. It was real shiny!

Ummmm, directed at me?
My comment wasn't directed to you and why you would even assume so is disturbing. The last couple it of sentences even more so.

You will never get a big block torque feel from a 318. However parts can be added to gain torque low down, and you can gear the car to make the most of the power made. I would not replace the heads myself. Not if you just want a little more snap. Cam, intake, headers, and ignition and you'll be fine.

Bingo.

 

[BDL]

Ummmm, directed at me?
My comment wasn't directed to you...

Sorry Dude Not that it's an excuse, but looking back, I answered that at 10:06 that night and was probably too tired to be answering anything. I should not have acted like my kids ;)

 

[rumblefish360]

No worries, were all good!

 

[451Mopar]

The issue with going to larger cams to make more power is that they make power by shifting the torque curve higher in the power band, and the low lower power band has less torque than stock. This is why a good torque converter will really make a difference, it allows the engine to operate in the engine power band. Usually, when you go to a larger cam, you want to increase the compression ratio which recovers some of the lost low end torque, and also boosts power throughout the power band. You could build a 500 HP 318, but the power band and idle would not be good for a street car, not to mention it would need more attention to maintance than most street cars get. A larger engine will make more torque with the same parts, so it can make the power in a lower RPM power band.

 

[57tbone]

Back in the day of the 340 ( a sweet small block ) I built a 318 short block with 340 heads, edelbrock torker intake, crane fireball cam, casler headers, holley 650 df -dp, and no one could catch me except a few big blocks 440's even 340's with 4 speed couldn't keep up! Cheap build for a wild ride but now big block 440 always for me.

 

[Hilljack68]

You need to compare the same year of engine to see the torque and power differences. Such as this 1971 list which shows that the 2bbl 360 has even more torque than the 4bbl 340.

Hey Photon, would you happen to have a link for the above information? I agree with you: I need to be comparing apples to apples. Good point.

 

[Photon440]

Hey Photon, would you happen to have a link for the above information? I agree with you: I need to be comparing apples to apples. Good point.

Not off the top of my head, but this page is quite similar.
http://www.mymopar.com/enginespecs.htm

 

[rumblefish360]

Back in the day of the 340 ( a sweet small block ) I built a 318 short block with 340 heads, edelbrock torker intake, crane fireball cam, casler headers, holley 650 df -dp, and no one could catch me except a few big blocks 440's even 340's with 4 speed couldn't keep up! Cheap build for a wild ride but now big block 440 always for me.

The 318 is the underdog only due to the bore size. If I can, (sonic check the block before attempting) I like to go .060 over if I can for 327 (.79) cubes.

*I think* it's Hensley engines that sonic checks 318's for there create stroker program. After sonic checking the 318... & the pass... they go to an4.00 bore with a 4.00 stroke crank.

FWIW, 4.00 X 3.31 = 332 cubes.

 

[moper]

I disagree. The 318 as a high performance engine is a slouch because of the heads. Bore size is almost irrelevant aside from tying to find cheaper but good pistons. Spend your money elsewhere than getting the biggest bores you can.
Every engine has the "perfect head". In Mopar's case in the 60s and 70s engines and their expected performance and rpm windows, the 340/360 ports and chambers are too big for the 318, great for the 340, and almost too small for the 360. So they decided on two basic types: smaller ports for 273 & 318, and bigger for 340/360.

It's just in the OPs case - heads are not a good return on investment and the levels wanted can be reached without major expenditure on them. Not that they wouldn't help in the right build.

 

[LXguy]

If you're going rebuild, I would recommend 360 no question. 318s aren't cheaper to build because of the lower cubic inches. Any dollar you spend machining a 318 is the same price as a 360.

I've got a 72 Satellite (sedan-don't get excited) and I've been dinking around with the stock 318 on my chassis dyno. In stock 100,000 mile form (though it leaks down good and has very good compression - for a 318) it made the almighty 130 rwhp at 3400 rpm. Torque was surprising at 200 ft lbs (but still mediocre for a V8). I installed a carefully chosen Summit cam (retain dynamic compression-be compatible with nitrous, sound cool) 4 bbl intake, 570 cfm carb, Hooker Super Comp headers and 2.5 inch dual exhaust. It *does* sound cool (people ask if its a 440-LOL) makes about 200 rwhp. Makes almost 300 rwhp on a hundred shot of nitrous. It is all done by 5000 RPM, with peak power coming in at 4950. Power is noticeably improved over stock, and I'm having great fun with it, but its a dog. It will hardly do a burnout without nitrous assistance.

The reason I did this was I built it for the Roadkill $3,000 hooptie challenge and took it on Drag Week. It did go 12.70 on a 150 shot, but I also lost a ujoint and broke the trans case, bent the driveshaft and hurt the rear end. Got it back together but missed the 3K hooptie race. :-(

Compare that with the junkyard shortblock 5.9 Magnum I built with EQ heads. I had 2500 in the motor from carb to pan, it made 335 rwhp on motor, and in a pretty decently figured out car it went 11.70s (on motor). At equal weight to the Satellite, I would expect it to have gone 11.90s, maybe 80s.

Obviously, ALL the power comes from cylinder heads and 318s have terrible heads. If I put 340/360 heads on it (and a superior 340/360 intake) the 318 would make more power than it does, but its still not going to make the same power or torque as a 360.

 

[Ironbuilt]

Thanks for the feedback. All good info. I like the Magnum idea if I can find one.

First, there is no substitute for cubic inches. That being said, Magnum engines are fairly easy to find in most junk yards. If money isn't an issue...