Cams for 318's

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toolmanmike said:
And it's just a story.
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Some stories are true albeit sometimes over embellished. alot of the nonsense I've been involved with in my life is all true yet most don't believe it . Folks today don't live like my generation did LOL...! Yeah, I have a lot of stories...
 
Dan the man said:
273's have a limited piston selection and the small bore affects the size valve's that can be used
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Agree but how much do you need for less than 300 cubes? Comparing these different cube engines against each other is ludicrous. In general terms, 300 horse is about the common sense limit for a 273. You might be able to squeeze 325-350 out of it with a exotic build but that's out of our league.
400 horse out of a 318, may be 450 out of a 340 or 360. 360's are a different combination and don't have the capability of that much more power with 20 extra cubes. Same with strokers. You might be able to get 500 horse out of a 408. May be more. Probably less unless you have deep pockets and a car than can use it. How much do you need on the street? Not that much. Too much power and you end up in the rhubarb or wrapped around a frickin tree. A some members here have over built their street car and ended up that way.
 
Here's my guess for a streeter;
.115 ftlbs per pound of car weight. and make it to the road none to early, cuz it will just go to tiresmoke. But at or near 35mph is where it will come in handy. Don't much care about absolute power, cuz I'm usually shutting down at 65 mph.
So for my 3650 pounds, I need about 420 ftlbs. and I want to run not more than 3.55s
So then I'll be looking at 420 x 3.55 =1491 into the rear axles, at peak
Ok then 420/360=1.167 ftlbs per cube; and that's a fairly easy goal
But with a 273, 420 becomes 1.538. So for a 3650 pounder with 3.23s this is Not a good place for the 273 to be.
But hey, at 2850pounds, that same .115 comes to 328 ftlbs, and 328/273=1.20 ftlbs per cube, and that's back to easy street.
So, I mean, it's all relative to the combo.
If my engine was smaller, I'd just have to shed some weight , to get back to .115ftlbs per pound
If my engine was stronger than .115, then I could either run more weight or less rear gear.
 
toolmanmike said:
Agree but how much do you need for less than 300 cubes? Comparing these different cube engines against each other is ludicrous. In general terms, 300 horse is about the common sense limit for a 273. You might be able to squeeze 325-350 out of it with a exotic build but that's out of our league.
400 horse out of a 318, may be 450 out of a 340 or 360. 360's are a different combination and don't have the capability of that much more power with 20 extra cubes. Same with strokers. You might be able to get 500 horse out of a 408. May be more. Probably less unless you have deep pockets and a car than can use it. How much do you need on the street? Not that much. Too much power and you end up in the rhubarb or wrapped around a frickin tree. A some members here have over built their street car and ended up that way.
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For a street car, torque is more important. 250 - 300 horsepower is more than plenty
 
AJ/FormS said:
Here's my guess for a streeter;
.115 ftlbs per pound of car weight. and make it to the road none to early, cuz it will just go to tiresmoke. But at or near 35mph is where it will come in handy. Don't much care about absolute power, cuz I'm usually shutting down at 65 mph.
So for my 3650 pounds, I need about 420 ftlbs. and I want to run not more than 3.55s
So then I'll be looking at 420 x 3.55 =1491 into the rear axles, at peak
Ok then 420/360=1.167 ftlbs per cube; and that's a fairly easy goal
But with a 273, 420 becomes 1.538. So for a 3650 pounder with 3.23s this is Not a good place for the 273 to be.
But hey, at 2850pounds, that same .115 comes to 328 ftlbs, and 328/273=1.20 ftlbs per cube, and that's back to easy street.
So, I mean, it's all relative to the combo.
If my engine was smaller, I'd just have to shed some weight , to get back to .115ftlbs per pound
If my engine was stronger than .115, then I could either run more weight or less rear gear.
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Why the focus on torque ? It's the hp at the rear tires that matters say 35 mph = 3000 rpm and 65 mph = 5500 rpm and your making 250 hp at 35 mph and 425 hp at 65 mph isn't all that matters is a 273/318 or even 440 make similar hp numbers at those mph ? Obviously each will be geared different to do so, and yes a 425 hp 273 would a lot and at high rpms with very deep gearing but theoretically should pull the same ?

Or we just accept what we make between 35-65 mph some be faster others be slower?
 
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273 said:
Why the focus on torque ? It's the hp at the rear tires that matters say 35 mph = 3000 rpm and 65 mph = 5500 rpm and your making 250 hp at 35 mph and 425 hp at 65 mph isn't all that matters is a 273/318 or even 440 make similar hp numbers at those mph ? Obviously each will be geared different to do so, and yes a 425 hp 273 would a lot and at high rpms with very deep gearing but theoretically should pull the same ?

Or we just accept what we make between 35-65 mph some be faster others be slower?
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Read the post again; You'll get it.
 
273 said:
Why the focus on torque ? It's the hp at the rear tires that matters say 35 mph = 3000 rpm and 65 mph = 5500 rpm and your making 250 hp at 35 mph and 425 hp at 65 mph isn't all that matters is a 273/318 or even 440 make similar hp numbers at those mph ? Obviously each will be geared different to do so, and yes a 425 hp 273 would a lot and at high rpms with very deep gearing but theoretically should pull the same ?

Or we just accept what we make between 35-65 mph some be faster others be slower?
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For a daily driver torque is what you need. Torque is what gets you moving
 
Dan the man said:
For a daily driver torque is what you need. Torque is what gets you moving
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Torque has zero movement to it, torque by itself does nothing, as soon as the crank starts to turn were now talking Power which is rpm and torque which is what moves, tows, accelerate etc.. your car, and we call that combination HP, torque is basically one powerstroke and hp is all the powerstrokes added up over time aka rpm. Even at 2000, 3000, 4000 rpm etc.
 
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Dan the man said:
For a daily driver torque is what you need. Torque is what gets you moving
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If you want low end torque, then a 318 is probably not for you. Even if it's built to maximize the low end , it's not going to have much . It's simply too small. But then my daily drivers for most of my life have been big blocks. Anyways... I think we have gotten a little off course with this thread. I thought this was " Cams for 318s ". I'm hoping to read some more real world quantified results like elapsed times and dyno pulls. A lot of the responses so far have been speculations and personal preferences and seat-o-the-pants. Gimme some numbers dammit!!!:)
 
forphorty said:
If you want low end torque, then a 318 is probably not for you. Even if it's built to maximize the low end , it's not going to have much . It's simply too small. But then my daily drivers for most of my life have been big blocks. Anyways... I think we have gotten a little off course with this thread. I thought this was " Cams for 318s ". I'm hoping to read some more real world quantified results like elapsed times and dyno pulls. A lot of the responses so far have been speculations and personal preferences and seat-o-the-pants. Gimme some numbers dammit!!!:)
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I couldn't give you time slips if I wanted to, as there isn't any tracks around here and dyno pulls, I don't have the funds to pay for something like that
 
Dan the man said:
I couldn't give you time slips if I wanted to, as there isn't any tracks around here and dyno pulls, I don't have the funds to pay for something like that
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I don't mean you specifically Dan. It would just be nice to see a few members post up some results other than " I got a 318 with a _ cam and it runs real good". A members personal perception of their cars performance doesn't tell me much. I had a friend that had a Trans Am back in the 80s. He thought it ran pretty good. Then he took it to the track . It ran 17s. If there are no tracks around, there is always this :Dragy Motorsports The Dragy is pretty danged accurate.
 
forphorty said:
I don't mean you specifically Dan. It would just be nice to see a few members post up some results other than " I got a 318 with a _ cam and it runs real good". A members personal perception of their cars performance doesn't tell me much. I had a friend that had a Trans Am back in the 80s. He thought it ran pretty good. Then he took it to the track . It ran 17s. If there are no tracks around, there is always this :Dragy Motorsports The Dragy is pretty danged accurate.
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I understand. I to wish someone could post dyno results along with their combination
 
I've mentioned several times that I'd love to see the same kind of analysis I've seen with big block cam selection or even stroker/340/360 cam selection applied to a reasonably mild build 318, with no other mods but, say a 4 barrel and dual exhaust, and maybe starting with one of the 9.2:1 factory engines.

I know we have several in-house persons with those kinds of qualifications.

There are at least a dozen off the shelf cams that qualify as a "next step up" or "two steps up" cam from the .400 lift of the factory part, without getting into the "mill the valve guides" lift area. Maybe all those in the .450 lift and under.

If only I had lottery winnings to figure out what to do with.....
 
Dan the man said:
I've dealt with the slant 6's, they are affected by their rpm limitations due to their long stroke and long connecting rods. I'm sure that with a good stall converter and gears you might be able to get some performance from them, but no matter how you look at it they are not known for their rpm capability.
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Except 170's that rev freely.
 
YY1 said:
I've mentioned several times that I'd love to see the same kind of analysis I've seen with big block cam selection or even stroker/340/360 cam selection applied to a reasonably mild build 318, with no other mods but, say a 4 barrel and dual exhaust, and maybe starting with one of the 9.2:1 factory engines.

I know we have several in-house persons with those kinds of qualifications.

There are at least a dozen off the shelf cams that qualify as a "next step up" or "two steps up" cam from the .400 lift of the factory part, without getting into the "mill the valve guides" lift area. Maybe all those in the .450 lift and under.

If only I had lottery winnings to figure out what to do with.....
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Agreed. It's speculative. Adding a bigger cam to a Teen rarely get's tested on a dyno or drag strip. I would like to do a little testing myself. A few passes on weekend with the duals and my 2 barrel. In a week or two, a few runs with a 4 barrel and LD4B only. Then a cam change and another test. There's a lot of cams out there that are bigger than stock without getting so big you need a converter and some 4.10's if you know what I mean. There again, which one is "best"? No correct answer there. May be choose 5 of the most popular cams?
 
Dartswinger70 said:
I remember on old fella telling me about a 56 Chevy wagon with a straight 6 and 3 on the tree beating a V8 Ford in a drag race. You never know and the driver has alot to do with it also. I tmakes me wonder if the 6 cylinder guy did some tricks to his engine back in the day.
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My uncle Wesley had a modded Chevy six back in the day, and my friends wife has one in a 50 Impala with aftermarket intake. That being said, another friend had a 69? Chevelle, 396, 4 speed, 850 cfm Holley, ran 18's in the quarter. You just don't know...
 
66fs said:
My uncle Wesley had a modded Chevy six back in the day, and my friends wife has one in a 50 Impala with aftermarket intake. That being said, another friend had a 69? Chevelle, 396, 4 speed, 850 cfm Holley, ran 18's in the quarter. You just don't know...
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They didn't have Impala's in 50.
 
66fs said:
Except 170's that rev freely.
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I've read some well thought out material that claims the 198 is the grail of a starting point for /6 builds.
 
YY1 said:
I've read some well thought out material that claims the 198 is the grail of a starting point for /6 builds.
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I built a 170 for the 64 Barracuda in the 70's when gas was too poor to run the 273. I was inspired by the "Baby Grand Nationals?" where the Mopar 170s came in first for as many as were entered. They never ran again since Chevy and Ford could not compete. A real sweet motor, not stock.
 
toolmanmike said:
DeLuxe, Styleline, Belair
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Bel Air, Thanks

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