I've seen A LOT of posts about making HP with a 318-So why is it so ???

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toolmanmike said:
Stock 318's have around 340 stock.
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Well, the magnum headed one Dulcich did years ago, that made 400hp...... made 382tq.

And the 420hp 360 I had on the dyno last year made 419tq.

340hp 340 made 378tq

331hp 360 made 367tq

I’m confident a mild 318 making around 320hp isn’t going to push the tq needle into the 450ft/lb range.
Not on the dyno here anyway.
 
but at what rpm do they get that torque number.
For the street you need good torque below 1500- 2000 rpm.
 
PRH said:
Well, the magnum headed one Dulcich did years ago, that made 400hp...... made 382tq.

And the 420hp 360 I had on the dyno last year made 419tq.

340hp 340 made 378tq

331hp 360 made 367tq

I’m confident a mild 318 making around 320hp isn’t going to push the tq needle into the 450ft/lb range.
Not on the dyno here anyway.
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Factory must be a lie then. LOL Just looking at the charts. I don't have a dyno.

power.PNG
 
Show me a dyno sheet of a n/a hot street motor built from a traditional “vintage” style platform(no variable cam timing) with peak tq in the 1500-2000 range, and you’ll be looking at a motor that has no top end power.
 
toolmanmike said:
Factory must be a lie then. LOL Just looking at the charts. I don't have a dyno.

View attachment 1715542245
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Where is the extra 110ft/lbs going to come from?

With these mild builds, the gain in hp comes from moving the tq peak up the power band, and having the curve hang on longer.
You don’t need to make more tq to make more hp.
If you looked at the dyno numbers I posted from 1990, you’ll see the motor didn’t even make as much tq as the factory rating...... yet it still made 60hp+ more than the factory rating.

Less peak tq...... but at a higher rpm.

There’s a reason the factory HP stuff came with higher stall converters and a little more gear.
The methods used to allow the motor to have more HP, reduce the output at the lower end of the power band.
That’s pretty much “hot rodding 101”.

For a 318 to make 450ft/lbs, the tq/ci would be 1.41.
This thread is slanted towards milder builds.
How many magazine builds can you find, that are in the vein of milder builds, where the tq output is 1.41/ci?
That’s 500 for a 355 Chevy
514 for a 365 Mopar
628 for a 446
650 for a 461
Out of mild street builds.

I never see those kinds of numbers out of that type of build.
It’s usually more like 1.10-1.20.
 
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no no...not peak at 1500 - 2000.But you need a useable number at lo rpm.
Member prh has offered his dyno sheets with his warm 318 with a cam and head porting in post #72. Compare them to Toolmanmikes' factory 318 torque numbers.

Oops..i was typing when your post came in and i missed it...
 
PRH said:
Where is the extra 110ft/lbs going to come from?.
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Sorry Back up the bus. I had a 252/261 .510 lift @ 106° cam in the dyno software. The rest is pocket ported heads, stock valves, headers, and a dual plane intake with a 600.
 
Any motor that’s making at or near 1hp/ci, is a “mild” build as far as I’m concerned.

So, if you have a “mild” 318, like I described above, and it’s making in the neighborhood of 1hp/ci......it’s going to be peaking at a fairly low rpm.....almost certainly under 5500.

Your response to my proposed mild 318 was 300hp/450tq.
So, where is the extra 110ft/lbs(over stock) coming from?

The reality is....... it’s not.
There is nothing about a build like this that’s going to result in a 32% increase in TQ output.
 
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PRH said:
Any motor that’s making at or near 1hp/ci, is a “mild” build as far as I’m concerned.

So, if you have a “mild” 318, like I described above, and it’s making in the neighborhood of 1hp/ci......it’s going to be peaking at a fairly low rpm.....almost certainly under 5500.

Your response to my proposed mild 318 was 300hp/450tq.
So, where is the extra 110ft/lbs(over stock) coming from?

The reality is....... it’s not.
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Like I said, I had a more than mild cam specs in the dyno program. And I see that your definition of mild and mine are 2 different things.
 
A 300 horse engine is mild if you are accustomed to 450-500 horse engines. It is a 30% increase which is quite an increase. Just my take.
 
I don’t think I’ve ever seen a n/a build, that retained the stock stroke, have a 30%+ increase in tq over the factory “gross” ratings, especially if you rule out the use of exotic heads.
Again, we’re talking about traditional platforms, without computer controlled engine management and/or variable cam timing.

Some examples of what you’d be seeing at 30% above factory gross ratings:

340 - 340 up to 442
383 - 425 up to 552
440 - 480 up to 624
440-6 - 490 up to 637
426 hemi - 490 up to 637
 
Heck, I made ifrc, 286hp and 265 tq to the rear wheels with a 318 in the car to the left without even trying...XE268H, Indy closed chamber LA-X heads, 10.3:1 comp and pistons .012 in the hole.
Edit: I found the dyno sheet...power at rear wheels remember...
View attachment 1715542255

dyno-sheet-jpg-1714938354-jpg.jpg
 
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I believe the factory rating for the 318 is optimistic to begin with. I've never seen a stock 318 2v make 230hp .
 
lomchivok said:
Heck, I made ifrc, 286hp and 265 tq to the rear wheels with a 318 in the car to the left without even trying...XE268H, Indy closed chamber LA-X heads, 10.3:1 comp and pistons .012 in the hole.
Edit: I found the dyno sheet...power at rear wheels remember...
View attachment 1715542255
Click to expand...

So if there was a 20% loss at the wheels you made 318 ft pounds at the flywheel.
 
justinp61 said:
So if there was a 20% loss at the wheels you made 318 ft pounds at the flywheel.
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And..... if it’s a car with a torque converter....... there would have been some torque multiplication going on...... that you don’t get on the engine dyno.
 
PRH said:
I don’t think I’ve ever seen a n/a build, that retained the stock stroke, have a 30%+ increase in tq over the factory “gross” ratings, especially if you rule out the use of exotic heads.
Again, we’re talking about traditional platforms, without computer controlled engine management and/or variable cam timing.

Some examples of what you’d be seeing at 30% above factory gross ratings:

340 - 340 up to 442
383 - 425 up to 552
440 - 480 up to 624
440-6 - 490 up to 637
426 hemi - 490 up to 637
Click to expand...
And a 300 horse 318 over the stock 230 horse rating.
 
An "honest" 300 HP in a light well prepared car is a "LOT" of fun.
 
In perspective, look at a 425 horse 426 Hemi. A 30% increase would be 552 horse.
 
I said torque.

It’s a whole different ball game.

If you can carry that stock 340ft/lb all the way to 6500rpm, you’d be making 420hp.

It’s easier to increase the HP than it is the TQ, if you’re not making the motor bigger.

For big HP gains, you try and make more TQ....... and move it up the power band.

340ft/lbs at various rpm = HP
2000- 129
2500- 161
3000- 194
3500- 226
4000- 258
4500- 291
5000- 323
5500- 356
6000- 388

The stock early 318 is rated at 230hp@4400.
In order to have 230hp@4400, that tq peak of 340ft/lbs@2400 has already dropped down to 274.5ft/lbs@4400.

My 318 from 30 years ago is making about 50ft/lbs more at 4400 than the stock 318 makes.
That moving of the tq peak from 2400 up to 4000, and its ability to carry the tq higher is where the extra 60hp comes from, even though the peak tq output was lower(328 vs 340).

Along those same lines........ for NA stuff...... anytime you see that the TQ number is noticeably higher than the HP....... it’s a pretty mild combo, and it’s peaking fairly early.
It means the tq curve drops off fairly quickly.......and it didn’t carry it high enough to have a better impact on the HP number.
Or...... in the case of some of the hotter factory combos, like a Hemi or L88 Chevy........ they’re giving you what the hp was at that rpm...... not what the “peak” hp was, or at what rpm it occurred.
 
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I don't know what the numbers were, but in the 80s I had a .030 over 318, basic rebuild as far as I know, that I stuck a set of 340J heads and matching factory 4 bbl intake on, using a tq and stock exhaust manifolds, no idea what the cam specs were, but that little motor in my rusty old 70 Dart GT sure embarrassed a lot of people. Granted that the 80s generally sucked in performance cars, but it was pretty respectable for the few $$$ I had invested.
 
missing linc said:
I don't know what the numbers were, but in the 80s I had a .030 over 318, basic rebuild as far as I know, that I stuck a set of 340J heads and matching factory 4 bbl intake on, using a tq and stock exhaust manifolds, no idea what the cam specs were, but that little motor in my rusty old 70 Dart GT sure embarrassed a lot of people. Granted that the 80s generally sucked in performance cars, but it was pretty respectable for the few $$$ I had invested.
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Oh man that is my first build all day long back in the early ‘80’s. The 318/4-spd w/4.10’s would eat Carmaros, firebirds and mustangs all day long. What a rip it was.

I had a big TQ on top a top of a LD-340-w/360 heads on a 318 with a Crane Cam.
 
PRH said:
I said torque.

It’s a whole different ball game.

If you can carry that stock 340ft/lb all the way to 6500rpm, you’d be making 420hp.

It’s easier to increase the HP than it is the TQ, if you’re not making the motor bigger.

For big HP gains, you try and make more TQ....... and move it up the power band.

340ft/lbs at various rpm = HP
2000- 129
2500- 161
3000- 194
3500- 226
4000- 258
4500- 291
5000- 323
5500- 356
6000- 388
Click to expand...
Yes you did. And I got talking about a 30% increase in horsepower. Like I said 3 times now, I don't have a dyno, you apparently do or have access to one. All I have to go by is a computer program. They are no more accurate and consistent than everybody's dynos or flow benches. This is what was programmed in the software. Now, I am just repeating what was on the screen.

318.PNG


318-2.PNG
 
My 30% is from you posting the TQ would go from 340 to 450.
That’s a 32% increase........ and my response was...... where is it coming from....... since I have never seen that.

Don’t take this the wrong way(and I realize you didn’t write the program), but...... 464ft/lbs@2000 from a 318?
Thats gonna get a firm “NFW” from me.
 
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