340 cam in a 318

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oldkimmer said:
I

It was so dead off the line that it wouldn’t even spin the tires. I suspect too low of compression and a stall converter would of certainly helped. Kim
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Man, that's crazy. But, With all due respect, the E is a Lil heavy...3:55s (3:91!!!s lol) or deeper w/ a stall would have work er up....But, Compression is an issue.. gotta have squeeze
 
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Wow.
A lot of opinions and testimony of who did what.
where is the OP?
He Seems to be concerned about compression, and I would understand why.
if you can’t bring the CR up, put the cam in 4* advanced and don’t look to rev it to 6k.
If like me, you have to work w what you have.
 
6pak said:
Wow.
A lot of opinions and testimony of who did what.
where is the OP?
He Seems to be concerned about compression, and I would understand why.
if you can’t bring the CR up, put the cam in 4* advanced and don’t look to rev it to 6k.
If like me, you have to work w what you have.
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I would like to see true budget performance tips for a 318, 340 / 360 cam, intake manifold and carburetor cfm, headers or exhaust manifolds, 2 1/4" or 2 1/2" exhaust. Gear ratio, which factory heads will do, etc. I have a budget to follow and I'm only wanting to add a little extra zip to the 318. Thanks everyone for your help and advice.
 
My 318 roller w 214/216*@.050” cam - 9.6:1 compression. Stock 302 heads , 904 trans w/ stock converter ,headers, performer intake & carb, 3.91 gears - ran strong. But only 14.5 sec at the track. Couldn’t hook up.
Was a lot of fun, and local State Trooper told me, personally (up close) , he had his eye out for me.
All the excitement i needed.
 
If you look at the specs of a "340 cam" you will see that's it's pretty much the same as a range of "Stage 1", "Towing" or "RV" cams that most grinders sell.
Most of these cams go from around 204@50 to 210 @50 on the intakes.
 
The 318 is not a huge engine. That is why cam selection requires careful thought, with respect to the rest of the combo such as diff ratio, weight, etc. Easy to convert it to canine status....
It is not like a stock 454 Chev where a bigger cam is going to automatically add more HP. As you increase cam duration, you reach a point where instead of HP increasing throughout the rpm range, you are just shifting the power, ie, power is depleted from the low end & added to the top end.
 
318willrun said:
I guess I'm assuming at least a 4bbl and dual exhaust, why would one install a 340 cam and leave the 2bbl on there. I haven't experienced a 340 cam with the factory 318 2bbl. I'd guess it would run just fine but .... .. .
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toolmanmike said:
You never know and we don't know.
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318willrun said:
I'd bet the 340 cam would do just fine with a stock 318 2bbl on top, I just haven't tried that.
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I did it back in my broke college days... It ran fine with a 2 bbl and stock 318 heads... Except my engine had 10.5 TRW pistons... It idled at 24" Hg and got 17.75 MPG...

I had to upgrade to 360 heads because the compression was too high and it would overheat on days that were over 80° F with the higher compression pistons... When I installed the 360 heads, I also put a square bore dual plane intake on it with a 600 Holley... That brought my idle vacuum down to 22.5" hg...


toolmanmike said:
At what rpm? How about needing a converter and/or rear gears to make it work. (318 with a 340 cam and nothing else) Asking for a friend.
:lol::lol: Another 318 cam thread. Here we go again.
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I had stock 904 trans and converter with 2.76 gears.... Tell your friend...
 
318willrun said:
I doubt I would do the 340 cam with a 2bbl with plans of leaving it a 2bbl. That's like polishing primer. I'd do just a 4bbl first and leave the stock 318 cam in before I did the reverse. Means the OP didn't state it, I'll give him the benefit of the doubt and say he'll be using a 4bbl.
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318willrun said:
If you already have the 340 cam, and a guy is on a 2 nickel budget, it's a great cam for a 318.
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I was in college and had 2 bad cylinders in the 318 in my Barracuda... My brother gave me a 72 318 short block with 10.5 TRW pistons... Then he offered me the stock cam from his Lil Red Express that he upgraded his cam on... I assembled the short block and installed the top end of the other 318 on it and installed it in my daily driver Barracuda for under $400 including Rhodes lifters, gaskets, oil, and antifreeze....

Broke college student, you throw together what you have...

Until I had the overheating problem... I spoke to my engine class professor and he told me my compression was too high and the mixture was self igniting before my spark and I had two flame fronts colliding due to the high compression and I needed to lower my compression... The 360 heads brought me down to 9.2... It ran great after that, I drove that engine to 500,000 miles....
 
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Professor Fate said:
What's all available? Very little at the moment. He might just be using what he can get or already has...
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Bakerlite said:
LOL.. the cam shortage ain't that bad..
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No cam shortage here...

I have over 2 dozen cams in my basement waiting for me to try them on different projects... Had them for years...

I degreed them myself with my son and we made a spread sheet so we can compare them apples to apples on the dyno program before we use them....

Cam shortage??? What cam shortage???
 
318willrun said:
Formula's, mathematics, can't because of..... shouldn't because of.... you'll be sorry on top of.....

wouldn't trade any calculations for first hand experience. some of us that have DONE it have testified. jury is in favor :)
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Ironracer said:
You know how many times I've got into it with a Truss Engineer or Architect, even a GC or Foreman. Real World experience is the Real Deal. Theory is great, but does it always work?
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Paralysis by analysis... :rolleyes:
 
Bakerlite said:
Well, I calculate piston to valve clearance.
Do you just bolt everything on and only realize you have an issue when you bend valves?
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Calculate piston to valve clearance???

I put some clay on top of the piston, then adjust the valve lash to zero and turn the engine over and measure the thickness of the valve imprints in the clay...

No calculation necessary, real world application eliminates any errors due to wrong assumptions that can be made in a calculation...
 
Dartswinger70 said:
318 heads suck making the 340 cam moot in a LA318 wit h LA 318 heads. I mean i suppose it would sound good and scare a teenage girl but it wont be that fast...it will fall on its face early in the rpm band...say at 5000 -5500 by all means do it and tell us what the end result is...
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The 318 heads have smaller ports which give the intake charge more velocity...

The guy who developed and tested the 5.7 L hemi heads on the flow bench once told me, "Velocity is torque"....
 
toolmanmike said:
Agree ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
There's always a lot of 318 cam threads when all of a sudden it has a 4 barrel and intake, headers, and some 340 or aluminum heads. Not the same as sliding a 340 cam into your stock 318-2 barrel with single exhaust. :lol::lol:
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318willrun said:
I'm pretty sure I'll do this... ^^ and I'm pretty sure the car will go faster than any factory stock 318 2bbl Duster. I firmly believe if you are going to install a 340 cam in a 318, a 4bbl and dual exhaust should by all means be part of the plan. But I'm confident that it would outperform the stock 318 cam if it was left as a 2bbl.
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Dartswinger70 said:
I had read somewhere that the stock LA 318 cam is pretty good in that application, you could just swap the intake and put a 4 barrel on it and it would run well.

of course I had gotten rid of my stock 318 cam long before I read that LOL!
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Dual exhaust is the first thing that should be done to increase the performance of a stock 318... Before any cam and intake change...

I had a 70 Dart Swinger with a stock 318... While on the way to Chicago from Detroit, I got the car to 60 MPH and nailed it to see how long it would take to get to 100 MPH on the highway... It took over a quarter mile or so, it felt like forever, the speedometer climbed very slowly....

I later had a mandrel bent 2 1/4" dual exhaust with street turbo mufflers installed on the car and then took it on the highway and did the same thing... It went from 60 MPH to 100 MPH in much less than a quarter mile... The speedometer climbed much faster....

I didn't measure it scientifically by marking the distance and measuring with a stop watch, you can tell by the seat of your pants that the dual exhaust really woke the stock 318 up... Even with a stock 2 bbl...

The stock single exhaust on the 318 is very restrictive and is the bottle neck in performance....
 
318willrun said:
I think my car fits the bill of these two quotes perfectly. Stock converter, 2.94 gears, but 272/.455 cam. Will it be like any other 318 2bbl ??? Slower??? Slightly faster??
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It will be slightly faster... :steering:
 
Dan the man said:
I would like to see true budget performance tips for a 318, 340 / 360 cam, intake manifold and carburetor cfm, headers or exhaust manifolds, 2 1/4" or 2 1/2" exhaust. Gear ratio, which factory heads will do, etc. I have a budget to follow and I'm only wanting to add a little extra zip to the 318. Thanks everyone for your help and advice.
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First add dual exhaust...

Then upgrade the cam, intake, and carb...


You will not get the full benefit of the cam, intake, and carb until you have dual exhaust....

2 1/4" exhaust is fine for a 318....


If you throw a set of 340/360 heads on a stock 318 bottom end, your compression will be down to 7.5... I've done that and measured it...

Either throw a set of 10.5 compression pistons in the 318 with the 340/360 heads to get you down to 9.2 compression, or install the 66 - 67 273/318 heads....

The stock 66 - 67 273/318 heads (casting number ending in 920) have closed chambers and will increase compression about .5 from the later stock 318 open chamber heads.... I'm currently putting an engine together with those heads... My head guy ported the 920's and installed 360 valves in them 1.88" intake and 1.60" exhaust... With a .040" thick head gasket, I will end up around 8.5 compression...
 
krazykuda said:
Calculate piston to valve clearance???

I put some clay on top of the piston
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That's after you get the cam...
Ever thought of calculating the clearance before you spec the cam? No one likes to get a new cam only to find it has .015 piston to valve..
Especially when you build engines for a living and the customer is paying.
 
Bakerlite said:
That's after you get the cam...
Ever thought of calculating the clearance before you spec the cam? No one likes to get a new cam only to find it has .015 piston to valve..
Especially when you build engines for a living and the customer is paying.
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How much measuring does it take to get the proper info to plug into the formula???
 
krazykuda said:
How much measuring does it take to get the proper info to plug into the formula???
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Here's an example..
If you called Bullet cams, gave them some basic engine specs and also how much valve drop you have at TDC, then they can pretty much tell you the limits of what you can install.
 
Shoooooooot !!!!!!!! That's what I forgot !!!! I forgot to check the piston to valve clearance when I put the cam in the Bombcycle (5.9 mag)
:eek:
 
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