360hp guesses

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Freakin A brother!
Freakin A....
PRH said:
Don’t take this the wrong way...... but without good dyno data...... the P/S calculator is somewhat useless.

What is does is show you whats “possible”.
If your car sucks, the numbers are just that........ numbers.

If you don’t know how much power you have, and what the car weighs...... you don’t really know what it “should” go.

I’ve heard the “you don’t race dynos” thing for almost 30 years.
But I can tell you this........ if you don’t make enough power to run the number you want to....... you’re never going to get there.

On the other hand if you need to make 500hp to reach the target, and you make 550hp....... but the P/S calculator shows you’re making 450hp....... you don’t need to waste any money on the motor.
Work on the car.
Click to expand...
 
PRH said:
Don’t take this the wrong way...... but without good dyno data...... the P/S calculator is somewhat useless.

What is does is show you whats “possible”.
If your car sucks, the numbers are just that........ numbers.

If you don’t know how much power you have, and what the car weighs...... you don’t really know what it “should” go.

I’ve heard the “you don’t race dynos” thing for almost 30 years.
But I can tell you this........ if you don’t make enough power to run the number you want to....... you’re never going to get there.

On the other hand if you need to make 500hp to reach the target, and you make 550hp....... but the P/S calculator shows you’re making 450hp....... you don’t need to waste any money on the motor.
Work on the car.
Click to expand...



I always laugh at the not racing dyno thing. The dyno is a tool.

I think I saw some of jpars time slips and he was around 118 MPH (IIRC) and I guessed at 3200 pounds and I think that's where the 430 came from.

But that's been awhile ago and I could be way out in the weeds.
 
PRH said:
Honestly........ if he’s trying to learn something by comparing his high Cr stroker with a tunnel ram to an 8:1 360 with a std Performer on it...... he’s totally lost........ and going deeper and deeper into the woods.

The only similarities between the two motors are they’re both SB Mopars.
Click to expand...
Post #55 I was just wondering if you had any major issues with the speed master heads.
As for my application I was hoping for lighter weight, to be able to get a thick enough custom head gasket to be able to run pump gas, and like I said "hopefully" a power gain over the heads I have...
I thought you were making a point of how the J heads may have worked better on the motor you were building then the aluminum heads? And I was just maybe giving an example of where the aluminum head would do better? I certainly wasn't comparing the two Motors heads up by any means or what they do....
My car has plenty enough horsepower to do what I want it to do. I thought lighter weight and extra horsepower would make it easier? LOL
I just have to work on the car and myself to get it to do the number I want...
That's no mystery..
Thank you for your time and insight...
 
I thought you were making a point of how the J heads may have worked better on the motor you were building then the aluminum heads?
Click to expand...

Let’s say that some very mildly bowl ported 1.88 valve J heads did in fact make the same, or slightly more power than the SM heads....... on that 8:1 hyd cammed 360 with a std Performer rpm on it.

How does that have any relavance as to what the SM heads would do on your motor?

It’s like all the panic that set in about the TF heads when that motor at Grays only made 450hp.

I’ll admit, I fell victim to the same type of thinking with this 360 in that I felt like the “better” heads would help elevate the power output to more than the sum of the rest of the parts.
They didn’t........ in the same way the TF heads didn’t elevate the power of that motor at Grays.

Trying to gauge how good something is based off it being used in an application where it’s benefits can’t be exploited, can easily lead you to false conclusions.

In the case of this 360....... the SM heads may not be “ideal” for a motor that mild........ but they’re still hard to beat when everything is taken into consideration.
It’s pretty easy in my area to have close to $1000 in some reburished iron heads (I just added up the costs for redoing some OE heads with Chevy valves and some bowl work, all new hardware, etc, and it came up to solidly over $1000) ...... and when you’re done, you have some nearly 50 year old refurbished stock heads that you’d probably struggle to sell for 1/2 what you have in them.
 
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If I'm investing in a head, it won't be on iron. Even the cheaper aluminum head will out perform an iron with the same amount of work. I should say, easier working aluminum, less time equals less money.
 
As was mentioned previously, the low power output of this build was primarily the result of poor planning.
If two items had been more carefully selected(pistons & manifold), the results would have been noticeably better.

And that type of scenario plays out pretty often.

Just as the potential of the TF heads shouldn’t be based solely on the numbers derived from the Grays build....... the potential of the SM heads shouldn’t be judged by this 360 build.
 
I think I saw some of jpars time slips and he was around 118 MPH (IIRC) and I guessed at 3200 pounds and I think that's where the 430 came from.
Click to expand...

It appears the current combo has gone 112.
At 3400lbs the P/S calc “shows” 365hp for 112.... which illustrates my point.
It’s not likely that’s all it would make if it were on the engine dyno.

Take Jpars build.........
410” stroker with mild ported heads, solid cam and tunnel ram.

Compare that to my friends 406” Pontiac stocker...... stock compression, unported stock heads that flow 215, .420 let lift at the valve camshaft, stock intake with Q-jet.

Think about the difference you'd expect to see on the dyno if you ran them back to back.
Forget about what the actual numbers are...... just how much difference you’d expect to see.

My friends Firebird also runs in that 3400lb weight range.

Using the P/S calc....... the Pontiac “shows” it’s better by 165hp(15mph higher).
 
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PRH said:
It appears the current combo has gone 112.
At 3400lbs the P/S calc “shows” 365hp for 112.... which illustrates my point.
It’s not likely that’s all it would make if it were on the engine dyno.

Take Jpars build.........
410” stroker with mild ported heads, solid cam and tunnel ram.

Compare that to my friends 406” Pontiac stocker...... stock compression, unported stock heads that flow 215, .420 let lift at the valve camshaft, stock intake with Q-jet.

Think about the difference you'd expect to see on the dyno if you ran them back to back.
Forget about what the actual numbers are...... just how much difference you’d expect to see.

My friends Firebird also runs in that 3400lb weight range.

Using the P/S calc....... the Pontiac “shows” it’s better by 165hp(15mph higher).
Click to expand...


Yeah, I forgot he defined the engine a bit with a smaller cam and maybe something else. That maybe where the 365 HP came from.

Sometimes so much information gets posted it all gets blended together.
 
Now
3300 with me.
Front 1750
Back 1550
112 in the 1/4

Before
3000 with me.
120 in the 1/4...
 
From an approximate 600 lift 270 at 50 duration to around 500 lift with about 235 - 245 duration. Took off electric water pump and put on manual...
 
j par said:
Now
3300 with me.
Front 1750
Back 1550
112 in the 1/4= shows 357hp

Before
3000 with me.
120 in the 1/4...= shows 397hp
Click to expand...

Did you make enough changes to the motor itself to lose 40hp?

From an approximate 600 lift 270 at 50 duration to around 500 lift with about 235 - 245 duration. Took off electric water pump and put on manual...
Click to expand...

Well....... that’s probably real close to 40hp worth between the two.

So, if you had the old cam and elec water pump in/on your motor with it on the dyno, compared to my buddies Pontiac...... how do you think they’d stack up?

My only point here is how important the car is when looking at the P/S calculators.

I will say this, with the big cam....... your motor should easily make more power than the Pontiac........ which just highlights the importance of the car, since his combo “shows” way more power than yours.
 
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j par said:
Now
3300 with me.
Front 1750
Back 1550
112 in the 1/4

Before
3000 with me.
120 in the 1/4...
Click to expand...


I also didn't know about the 300 pound weight gain.

PHR is correct though. Without dyno numbers the P/S calculator is just guessing.

As an example, if the engine was on the pump and made 520 and then went out and had MPH of say 480 you might think there is nothing wrong, because 480 isn't a bad HP number. In reality, you may have ignition, fuel or some power related issues you may be missing.

The opposite is true.

You can have an engine down on power and hooking like jack the bear that makes the ET look real good while the engine is down on power.

All the numbers are interconnected. We won't even get into the discussion of looking at incremental numbers.
 
One thing when using the P/S calcs is you need to apply some common sense and look at the overall combo and make the intuitive mental adjustments.

I’ve been talking to a guy who’s not super happy with his combo.
He had a motor done and was expecting it to be faster than it is.
Not only on the time slip, but from behind the wheel.
It was not dynoed.
We discussed what the combo was....... I told him it should be an easy 460-475hp build.
Then I had him tell me about the overall combo, and I told him what I thought it would run........ and that it would likely show about 100hp low.
He said I nailed it with the predicted ET, and I looked at the P/S calc and it showed 365hp.

He’s made a few tweaks, picked up a couple tenths....... no improvement in speed(so it still shows 365hp)...... which I’m pretty sure is a lifter/valve float issue.

Like I said previously, I like to use it as a yardstick of what’s “possible”.

Most decent street/strip and basic bracket combos should be able to run within 10% of what the engine dyno numbers indicate....... provided the car combo is pretty close, and you’re not racing at higher elevations.
Typical manual trans cars will usually be a little farther off in ET vs speed.
The 60’ times are slower than their auto trans counterparts most of the time.
So, for a 3500lb auto car...... say the motor dynos at 500hp.......90% of that is 450hp.
450hp@3500lbs shows [email protected].
This is if the car is set up pretty optimally...... correct gearing and stall, slicks, good fuel system, ign, etc.
For each thing that isn’t optimum, the performance will come down a tick.
If you’re not within the 10%........ it’s usually more effective to address issues with the “car” as opposed to the motor.

With manual trans cars, that’s often easier said than done....... or not really possible at all.
Any type of launch technique that doesn’t allow for full throttle balls to the wall type launches will just kill the ET.
With many street/strip cars...... that type of launch with slicks results in broken parts....... so often times the leave, and there for ET, is compromised in the name of reliability.
But this can really skew the numbers on the P/S calcs.
 
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PRH said:
One thing when using the P/S calcs is you need to apply some common sense and look at the overall combo and make the intuitive mental adjustments.

I’ve been talking to a guy who’s not super happy with his combo.
He had a motor done and was expecting it to be faster than it is.
Not only on the time slip, but from behind the wheel.
It was not dynoed.
We discussed what the combo was....... I told him it should be an easy 460-475hp build.
Then I had him tell me about the overall combo, and I told him what I thought it would run........ and that it would likely show about 100hp low.
He said I nailed it with the predicted ET, and I looked at the P/S calc and it showed 365hp.

He’s made a few tweaks, picked up a couple tenths....... no improvement in speed(so it still shows 365hp)...... which I’m pretty sure is a lifter/valve float issue.

Like I said previously, I like to use it as a yardstick of what’s “possible”.

Most decent street/strip and basic bracket combos should be able to run within 10% of what the engine dyno numbers indicate....... provided the car combo is pretty close, and you’re not racing at higher elevations.
Typical manual trans cars will usually be a little farther off in ET vs speed.
The 60’ times are slower than their auto trans counterparts most of the time.
So, for a 3500lb auto car...... say the motor dynos at 500hp.......90% of that is 450hp.
450hp@3500lbs shows [email protected].
This is if the car is set up pretty optimally...... correct gearing and stall, slicks, good fuel system, ign, etc.
For each thing that isn’t optimum, the performance will come down a tick.
If you’re not within the 10%........ it’s usually more effective to address issues with the “car” as opposed to the motor.

With manual trans cars, that’s often easier said than done....... or not really possible at all.
Any type of launch technique that doesn’t allow for full throttle balls to the wall type launches will just kill the ET.
With many street/strip cars...... that type of launch with slicks results in broken parts....... so often times the leave, and there for ET, is compromised in the name of reliability.
But this can really skew the numbers on the P/S calcs.
Click to expand...
I've broken parts at the start line. I'm very happy with my current configuration. After 10 passes at 2 tracks I'm within 4 tenths of my "goal et".
I've been working on several ideas on how to get to my goal with out having to do it all in my 60 foot. Which is you pointed out can be hard on parts. For now I'm seeing what I can do just fine tuning Jets timing and such.
 
The target is 11.9X?

I’d say.......with a 60’ time in low 1.80’s, you’ll probably need to go 113-114 to get into the 11’s....... with the rest of the run being pretty solid.
 
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