Moparts
torque per cube?
Posted By: gregsdart
torque per cube? - 01/10/10 05:03 PM
I am curious what some of the best packages produce for torque per cube. I and I think a lot of other guys would like to see how the various heads work, and what is possible. Non mopar combos wellcome for comparison.
Please give head type, induction, cam type (specs also), usage. Thanks, Greg
Posted By: blownzoom440
Re: torque per cue? - 01/10/10 05:14 PM
930 TQ at 3800/989hp at 6100
446 ci,3.75 stroke,iron 346 heads 12lbs of boost,8-71 2x850 carbs on race gas.
Posted By: Old School
Re: torque per cube? - 01/10/10 11:32 PM
my 580" made 790 ftlbs.
14-1cr
440-3 w/ 1120 dominator
572-13 365 cc 388 cfm @.800"
solid roller .800" [Email]290@.050[/Email]
it's in a street car,was built for torque.
Posted By: HotRodDave
Re: torque per cube? - 01/11/10 03:26 AM
I don't know if this is acurate or not but I have heard from a couple different engine builders that if your goal is the biggest number of tq you should run a cam around
236@.050 but they state (obviously)that this will vary some from one combo to the other.
For a bunch of examples of high specific TQ look at the last few engine masters competitions, very interesting stuff in there
Posted By: Cab_Burge
Re: torque per cube? - 01/11/10 03:37 AM
440 block 4.38x3.91 stroke 12.8 to 1 comp. ratio,B1-BS heads M.W. port, tunnel ram with two 750 D.P, Crane solid roller cam 273 @ .050 721.8 HP @7000 RPM and 615.4 ft. lbs.@ 5400 RPM. My 518 CI low deck pump gas motor, 4.375 bore, 4.300 stroke, 10.29 to 1 comp. ratio. Eddy RPM 440 size cnc standard size port, six pak intake & carbs. 718 hp at 5800 rpm, 744 ft. lbs at 4500 rpm. This motor with a 2.50 stroke crank, 9.25 to 1 comp. ratio and ported 906 heads made 612 hp at 5600 rpm with 644 ft. lbs at 4000 rpm. It seems on the pump gas motors I make the lower comp. ratio motors make more torque than HP. The N/A higher comp. ratio race motors on race gas make more HP than torque
Posted By: Al_Alguire
Re: torque per cube? - 01/11/10 06:12 AM
Well my junk aint gonna impress anyone at 775ft/lbs....For sure. Interesting ot see what we get here.
Posted By: dodgeboy11
Re: torque per cube? - 01/11/10 06:29 AM
Just dynoed a 555" bb chev. 11:1 CR with AFR 325 CNC'd chambers only. Short runner went 335 cfm, didn't flow the long one. Decent GM dual plane, solid roller with, I believe, 256/264 on a 112 with 650'ish lift. Pump gas, finally squeaked 653 hp @ 5800 rpm and peaked 680 ft lbs @ 4200 rpm. 3500-5700 it never dropped below 600 ft lbs. Going into a '69 corvette. Oughta be a halfshaft bustin' beast. If it ever gets traction.
Also built a 408 mopar. 11.5:1 compression with Indy oval port heads that I ported on. 570 hp @ 6200 rpm. Hydraulic roller that really is too small for this engine, but it'll make a nice little package that shouldn't require much maintenance. Torque was 539 ft lbs @ 5000-5100 rpm. 500 ft lbs from 4300-5900. This was on 110 leaded, but only because I was afraid of loading the motor that hard on the dyno on pump fuel.
Posted By: Bigcube
Re: torque per cube? - 01/11/10 11:19 AM
I have some interesting data on this. I'll take a look at the sheets tonight but a simple thing like too small of headers picked up quite a bit of TQ on my motor.
Posted By: gregsdart
Re: torque per cube? - 01/11/10 04:12 PM
Thanks for the inputs guys. It is interesting to see real world results, to see kinda what happens at various cam configurations, headflow vs cubes, etc.
What originally got me to thinking up this post is wondering where is the best range to build the most torque per cube, and what effects it all. Stuff like induction ram tuning, exhaust tuning, rpm, etc. I was looking over the engine masters article in Mopar muscle ,got a lot out of that.
The winner almost beat the roller cam entrys in torque production with a flat tappet cam and a tunnelram setup. The flat tappet motors didn't make as much hp, but as shown by the winner, built some very respctable torque. The winner was making 1.204 ft lbs per cube, the best roller combo 1.24. The differance in combos, the flat tappet combo had the tr intake and 452 cubes, the roller combo had more cubes (500), single/dominator combo.
Posted By: SportF
Re: torque per cube? - 01/11/10 05:30 PM
I am kinda curious why you would build for torque, assuming a race or even a pleasure motor. If you look at all the torque and horse power figures, torque on a decent motor is always within about 10% of HP. When you get like a nail head Buick that makes 350 HP and 450 pounds of torque, or a diesel that makes 300 hp and 600 ft pounds, well that's either a failure to rev or something else wrong.
I have heard guys talk and say it’s the torque that moves the car. Well, would you want 10,000 pounds of torque at 5 RPM? I don't think so, it wouldn't get you anywhere. I'd like to hear other opinions on this, but if it’s a race motor, you want power, don't you? That equates to RPM's and torque put together. Build for horse power and the torque will come.
Posted By: Old School
Re: torque per cube? - 01/11/10 05:35 PM
Quote:
I am kinda curious why you would build for torque, assuming a race or even a pleasure motor. If you look at all the torque and horse power figures, torque on a decent motor is always within about 10% of HP. When you get like a nail head Buick that makes 350 HP and 450 pounds of torque, or a diesel that makes 300 hp and 600 ft pounds, well that's either a failure to rev or something else wrong.
I have heard guys talk and say it’s the torque that moves the car. Well, would you want 10,000 pounds of torque at 5 RPM? I don't think so, it wouldn't get you anywhere. I'd like to hear other opinions on this, but if it’s a race motor, you want power, don't you? That equates to RPM's and torque put together. Build for horse power and the torque will come.
on my street cars,i build for torque and let the horsepower fall where it will. 
Posted By: patrick
Re: torque per cube? - 01/11/10 06:08 PM
I've never seen a naturally aspirated motor make more than 1.4 lb-ft per cube.....most well designed/built make 1.2-1.3
Posted By: Avenger
Re: torque per cube? - 01/11/10 06:27 PM
Quote:
Quote:
I am kinda curious why you would build for torque, assuming a race or even a pleasure motor. If you look at all the torque and horse power figures, torque on a decent motor is always within about 10% of HP. When you get like a nail head Buick that makes 350 HP and 450 pounds of torque, or a diesel that makes 300 hp and 600 ft pounds, well that's either a failure to rev or something else wrong.
I have heard guys talk and say it’s the torque that moves the car. Well, would you want 10,000 pounds of torque at 5 RPM? I don't think so, it wouldn't get you anywhere. I'd like to hear other opinions on this, but if it’s a race motor, you want power, don't you? That equates to RPM's and torque put together. Build for horse power and the torque will come.
on my street cars,i build for torque and let the horsepower fall where it will.
My 2 cents for what it's worth. Building for torque is a good thing. Torque and power (HP) are linked by the hip (so to speak), because of the fact that horsepower equals torque (in ft-pounds) times RPM divided by 5250, so people who talk as if they are independent of each other don't really understand the concept. If you have a given torque curve for an engine, you have the horsepower curve also. Knowing how these two numbers work together with each other lets you better understand some of the do's and don't of what you might read on building efficient engines. RPM plays a hugh role also.
Hope i'm not off bases with the initial question.
Posted By: gregsdart
Re: torque per cube? - 01/11/10 06:42 PM
It is great to read about combos, and what they produce. Torque, and where it is, combined with how the curve is shaped, mean everything in a motor plan. In the end, that is what will produce the usable hp you are shooting for.
An example; My motor leaves the line at 6600 rpm, stays at 6600 for 2/3 of each gear. Probably would be a good idea to favor max torque production right there. So I want to know every thing I can about what will make best torque there.
Posted By: MuscleMike
Re: torque per cube? - 01/11/10 07:09 PM
622", 11.3:1, solid roller, 150psi cranking, 92 speedway premium, 1.4 per cid.
B1 heads are odd because they don't flow enough air relative to the port size (or CSA: cross section area) on a big inch combo the port is big enough to support the cid but the flow isn't there to support RPM so the engines tend to nose over early.
These King Krate combos make STUPID torque and are all done by 6500. Cam and cross sectional area very important to making torque. You want to have enough duration to make max torque before you run out of CSA to support RPM for any given CID.
Mike @MM
Posted By: MuscleMike
Re: torque per cube? - 01/11/10 07:11 PM
Forgot dyno sheet. its kind of grainy but it make 882 FT lbs 4500 and 915 @6000 RPM's. Over 800 ft lbs from 3200-6000 RPMs
Posted By: Barnstorm
Re: torque per cube? - 01/11/10 07:55 PM
500in 440-1 14.5-1 380cfm 740 lift roller, 1150 dom.
820hp@7200,
718tq@5200...1.436.
Posted By: street_dart
Re: torque per cube? - 01/11/10 10:43 PM
766Lbs@5100rpm 499" (4.15x4.375") B1BS Mw port 67cc chamber. 13.7-1comp. Indy inake (ported). 1050(9375)holley. roller cam .725/.715lift 276/284@.050dur.
headders 2"x34"-4"colector open.
= 1.53Tq/"
Posted By: Old School
Re: torque per cube? - 01/11/10 10:52 PM
Quote:
Quote:
I am kinda curious why you would build for torque, assuming a race or even a pleasure motor. If you look at all the torque and horse power figures, torque on a decent motor is always within about 10% of HP. When you get like a nail head Buick that makes 350 HP and 450 pounds of torque, or a diesel that makes 300 hp and 600 ft pounds, well that's either a failure to rev or something else wrong.
I have heard guys talk and say it’s the torque that moves the car. Well, would you want 10,000 pounds of torque at 5 RPM? I don't think so, it wouldn't get you anywhere. I'd like to hear other opinions on this, but if it’s a race motor, you want power, don't you? That equates to RPM's and torque put together. Build for horse power and the torque will come.
on my street cars,i build for torque and let the horsepower fall where it will.
heres my torque curve,flat as a table
this is on an engine dyno.i was able to get 34 more ftlbs while tunning on a chassis dyno.it made a total of 790 ftlb 
Posted By: gregsdart
Re: torque per cube? - 01/12/10 01:19 AM
Thanks a lot for the input guys, really helps all of us learn more!!!!Keep em coming, and Muscle Mike, really liked the explanation of your combo.
Posted By: Diablo
Re: torque per cube? - 01/12/10 01:45 AM
I don't have much Dyno info on my 636ci since we only really ran it on there a few times to make sure everything was alright.
Made 913 lb-ft@ 5700rpm (dyno didnt pull it down any lower)
Made 801 lb-ft@ 7100rpm (didnt run it much higher then that on the dyno)
Those numbers come in right around 1.4 per cube
Posted By: B1Fish540
Re: torque per cube? - 01/12/10 03:57 AM
Quote:
622", 11.3:1, solid roller, 150psi cranking, 92 speedway premium, 1.4 per cid.
B1 heads are odd because they don't flow enough air relative to the port size (or CSA: cross section area) on a big inch combo the port is big enough to support the cid but the flow isn't there to support RPM so the engines tend to nose over early.
Mike @MM
Thats because they are a wedge and have limited valve size, right? Does the TS also lack flow for big inch motors?
Posted By: G_bob
Re: torque per cube? - 01/12/10 05:08 AM
505", 13:1, 4.40" bore x 4.15 stroke,
Victor max wedge heads, 2.20"/1.81 valve, 355/284 cfm @ .700.
Solid roller 264/268 @ .050, .716 gross lift with 1.7 rockers
Super victor intake, 1050-8896 dominator, 2"/3.5" hooker super comp headers
Made 683 tq @ 5000, 768 hp @ 6500
If I did my math right, that's 1.35 ft lb per cube.
Made 689 and 776 with a 1.5" tapered spacer.
505" on the IMM dyno
Posted By: dodgeboy11
Re: torque per cube? - 01/12/10 05:44 AM
I prefer to build a race engine for hp. If I want to build a tow truck I'll build for torque.
Posted By: emarine01
Re: torque per cube? - 01/12/10 02:02 PM
Peek torque comes @ peek VE, the trick is to keep torque or VE as high as possible past 5250 for as long as possible, than you have a engine that will pull hard thru the power band, the longer the torque curve the higher the power band, the more rotational speed in RPM = more HP<disclaimer> this is the personal opinion of a small block engine guy with just a few years of experience, I could be totally wrong
Posted By: gregsdart
Re: torque per cube? - 01/12/10 02:21 PM
Quote:
I prefer to build a race engine for hp. If I want to build a tow truck I'll build for torque.
I bet you would agree, that after you reach a very high hp level, you will be looking to enhance every step of the intended rpm range, right? Even if you sacrifice a peak hp spot, but spread out the torque, creating more average hp.
My best hp dyno sheet was not my best dyno pull, the one with the best average hp by 3 or 5 hp is my best overall combo.
One of my reasons for starting this post was to learn ways to move the torque peak up, as my combo goes fastest with the converter way over the present torque high point. Anything I can do to move that point higher will help, provided I don't loose too much in the process.
Posted By: Anonymous
Post deleted by Defbob - 01/12/10 02:26 PM
Posted By: gregsdart
Re: torque per cue? - 01/12/10 02:31 PM
Hemifred, that is some serious power! I notice it makes 1.548 ft lbs per cube at 6,000 rpm. That is about as efficient a motor as I have seen listed so far!
Posted By: HotRodDave
Re: torque per cube? - 01/12/10 04:21 PM
Quote:
I am kinda curious why you would build for torque, assuming a race or even a pleasure motor. If you look at all the torque and horse power figures, torque on a decent motor is always within about 10% of HP. When you get like a nail head Buick that makes 350 HP and 450 pounds of torque, or a diesel that makes 300 hp and 600 ft pounds, well that's either a failure to rev or something else wrong.
I have heard guys talk and say it’s the torque that moves the car. Well, would you want 10,000 pounds of torque at 5 RPM? I don't think so, it wouldn't get you anywhere. I'd like to hear other opinions on this, but if it’s a race motor, you want power, don't you? That equates to RPM's and torque put together. Build for horse power and the torque will come.
Build for HP and the TQ will come through really low gear ratios and high stall TQ converters, things that make a car less fun to drive. This is why I build big high TQ motors for the street so I don't have to multiply it back into TQ 
What ever ones end goal is (especially in a drag car is) to put as much TQ to the rear wheels as possible you can get it through high RPM power being multiplied back into TQ or just plain big TQ. It is just that big HP seels motors.
Posted By: HotRodDave
Re: torque per cube? - 01/12/10 04:30 PM
An example of what I was saying would be a 440 makeing 500 hp and 600Lbs TQ you could run it with 3.23 gears and have almost 2000 Lbs TQ at the rear axle(in direct gear for simplicity sake). On the other hand if you had a 302 ferd that made 500 hp you could go just as fast in an other wise equal car but you would only have 411 lbs tq (asumeing same tq per cube) in that motor so you would have to run a 4.86 gear to put the same amount of TQ to the rear axle in direct gear. It is TQ at the rear wheels that gets the car moveing.
Posted By: SportF
Re: torque per cube? - 01/12/10 05:02 PM
Would you rather have 500 HP and 600 pounds of torque, or 550 HP and 600 pounds of torque? I think you'd want the revs that make that 550. If you do have a combo of 500 HP and 600 pounds of torque there is probably something wrong with the combo and not as effiecent as it should be. I guess I agree its torque at the rear that moves the car, but that torque has to come at RPM's, which is power...which accelerate the car, eh?
Posted By: emarine01
Re: torque per cube? - 01/12/10 05:31 PM
I think dollars have to be in this equation, Big HP takes more RPM and more money, Unless you have unlimited funds, Engines should be looked @ as a trade between power and dollars, I am a small block guy so I look more @ dyno sheets from builders Like RJ & Brian , Brett and a few others, Some of the art of engine building is to provide good power bands with torque and HP with in the dollars allowed,That being said I wish I had a lot more disposable income
Posted By: gregsdart
Re: torque per cube? - 01/12/10 06:36 PM
"That being said I wish I had a lot more disposable income"
Ain't that the truth!
Chasing power and et is darned expensive after you get up there a ways!
Posted By: gregsdart
Re: torque per cube? - 01/12/10 06:37 PM
Hemifred, what are the specs on that 655 hemi? head type? new 99 or second gen?
Posted By: supercomp
Re: torque per cube? - 01/12/10 06:40 PM
Here is two of our dyno sheets. 451 with pocket ported SR Heads and a m1 intake.
278 @ .050 with .660 lift roller.
500 ci B1 fully ported.
Posted By: B1Fish540
Re: torque per cube? - 01/12/10 08:10 PM
Quote:
Hemifred, what are the specs on that 655 hemi? head type? new 99 or second gen?
Greg, thats a millinium headed motor. We've discussed DTs hemi on other threads, thats the one Fred now owns, iirc.
My 540 with unported Originals has 743 lbs at 4500rpm. Cam is a 280 at .05 endurance roller and CR is 12.5. HP was right at 800/6500rpm.
Posted By: Anonymous
Post deleted by Defbob - 01/12/10 08:33 PM
Posted By: mbogina
Re: torque per cube? - 01/12/10 09:03 PM
The current crop of Comp Eliminater and Pro Stock engines have reached a development point that 1.6 Ft Lbs of Torque per Cube and slightly over 2.6 HP per Cube are realistic goals. Building for Torque vs Horsepower is something of a misnomer, since a big HP number is really just a conversion of a big Torque number at a higher RPM. A rising or dead flat torque curve is the fastest way to increase HP, since the same or higher TQ number at a higher RPM increses the HP equation the quickest.
TQ x RPM/5250=HP
In order to move the location of the TQ peak and/or increase the TQ output, generally the MCSA will need to increase, it seems to be a defined TQ predicter for a well developed engine.
Posted By: MuscleMike
Re: torque per cube? - 01/12/10 09:55 PM
HP DOES NOT EXIST per sa.
Torque is the only measure of rotational energy PERIOD!
HP is torque x RPM/5252.
Cam profile, head flow, CSA and engine volume (CID) can drastically effect where and when you make torque.
HP is only the ability to make torque a RPM.
A big head on a small engine will make lousy low speed torque but it will be able to support RPM so it makes HP at a higher RPM. The converse is true if you have a small head on a big engine, it will make gobbs of torque but the small head will not allow the engine to breath at higher RPM to make more HP.
Thats why 440's were always perceived as torquey engines. A good amount of cubic inches with a head better suited for 350-370" engine.
Class over
Mike @MM
Posted By: blownzoom440
Re: torque per cube? - 01/12/10 10:46 PM
now can you take the info from the equation and find the CSA or head flow or VE of the enging?
Posted By: B1Fish540
Re: torque per cube? - 01/12/10 11:30 PM
Quote:
Thats why 440's were always perceived as torquey engines. A good amount of cubic inches with a head better suited for 350-370" engine.
Class over
Mike @MM
I think we all have taken head flow 101, Mike. What needs to be talked about more is specifics.
btw, all OEM heads back in the day were small valve, small port, except for the Hemi and the BB chev(well, the boss ford also). Take the 455 Buick, it had even smaller valves than the 440. These things made huge TQ for propelling the big Buicks down the road.
Why a big motor responds this way, tho, is still a little murkey. Is the small valve producing a faster/richer charge earlier in the RPM range resulting in more power? And is that alone producing more torque? My question i guess is: Does intake velocity account for the low RPM torque in these engines, along with the longer stroke/displacement?
Posted By: 572DartPost
Re: torque per cube? - 01/12/10 11:57 PM
572 pumpgas hemi...looks like 1.38 per cube
Posted By: dstryr
Re: torque per cube? - 01/13/10 03:46 AM
Quote:
I am curious what some of the best packages produce for torque per cube. I and I think a lot of other guys would like to see how the various heads work, and what is possible. Non mopar combos wellcome for comparison.
Please give head type, induction, cam type (specs also), usage. Thanks, Greg
Greg,
This is my 505" street car engine that was finished up in November:
Here are the basics:
1966 440 block +.030"
440 Source 512" kit
440 Source heads, valve job, back-cut valves
Porting: 254cfm initial, 283 after porting on the intake side
.044" ROL head gasket
Squared and decked, pistons -.004"
10.2:1 compr. approx.
Comp Cams XS290S
Comp Cams EDM lifters
Smith Bros Pushrods
Harland Sharp 1.5 roller rockers S70015K
'69 6 bbl induction system with Promax outboard metering plates, center metering block, and rear adj. base
Stock dist. with Pertronix Ignitor conversion and Flamethrower coil
Doug's D452 2" headers
598hp, 651 lbs/ft torque on 91 octane pump gas.
1.29 lbs/ft tq/cubic inch
Posted By: dodgeboy11
Re: torque per cube? - 01/13/10 05:55 AM
Quote:
The converse is true if you have a small head on a big engine, it will make gobbs of torque but the small head will not allow the engine to breath at higher RPM to make more HP.
I agree in theory Mike, but if you have a good head on the big motor it may not make the amount of torque at low rpm that the small head will but it will produce more torque overall than the smaller head can possibly produce. Which I am sure you know.
Posted By: MuscleMike
Re: torque per cube? - 01/13/10 11:35 AM
Not necessarly. I'll refer back to the King Krate example. OVER 800 ft/lbs from 3200-6000 RPM with a peak torque of 882. It is ALL about combination! there is no plug in formula to get "X torque for X RPM". CID, Head flow, CSA, duration, lobe separation angle and compresion ratio ALL effect ones ablity to make torque.
If the small head theory "always makes more torque" then a 906 with a hydraulic cam on a 622 should make even MORE torque than B1's???? NO WAY! You still have to be able to support the cubic inches and that requires CSA, flow and duration.
Mike @MM
Posted By: SportF
Re: torque per cube? - 01/13/10 12:45 PM
This has turned into a very interesting discussion. Let me step back and propose this. Say you have a lawn mower engine, and you go full throttle and they go up to about 4K in revs, no load. It can't rev faster because the air in and out just won't let it go any faster, that’s as fast as it can rev. At that "no load" 4K rpm, you can rub a stick on the shaft and slow it down because it has virtually no torque there as it is running at max rpm without a load. Now, change that engine however you want and now this same engine will rev "no load" to 5K. Now there won't be any torque at that 5K, but what now happens at 4K. You got torque there now! So doesn't the ability to run higher revs move the whole torque curve up? I think it has to. This lawn mower engine that now goes to 5K has more power than that engine that only went to 4K. And if everything is reasonably efficient, I bet with this motor too, the HP and TQ are within 10% of each other, same as all the motors listed this topic.
Posted By: mbogina
Re: torque per cube? - 01/13/10 11:32 PM
SportF- Your logic is that spinning the motor higher will make more HP, but this is not true. Once the TQ curve drops faster than the math converts to bigger HP due to the increase of RPM, the motor has reached its peak HP and turning more RPM will not make more HP. On my SS Hemi, if I happen to make peak HP at 8000 RPM, turning it up to 9000 will definitely NOT produce more HP, the TQ curve is simply falling too fast. A motor under no load makes very little TQ. Most Dyno's are "water brakes", pretty hard to compress that water, and the "water always wins", loading the motor to its "stall point" prior to the operater "releasing" the water in a controlled manner to allow the motor to accelerate. In your previous post, you stated that most motors peak TQ production will be within 10% of peak HP, I have not found that to be true. My SS motor is closer to 40%, the last 572 I dyno'ed was around 15%, a stock 1970 rated 440-4V from the factory was 31%, a stock GS 455 motor was around 50%, the last 505 Hemi I dyno'ed was 20%.........
Posted By: Al_Alguire
Re: torque per cube? - 01/14/10 05:09 AM
Quote:
I've never seen a naturally aspirated motor make more than 1.4 lb-ft per cube.....most well designed/built make 1.2-1.3
Mine is above that number. 525" B1MC making 775ft/lbs(775.8 to be exact)at 6300 RPM. that was on the previous fuel, new fuel has picked up a solid 2mph over the old stuff. That would put me 1.48, rounding up. FWIW my heads flow 457.2 cfm at .900". Cam is on the conservative side 280/296 851"/820 with a 113 LSA. The compression ratio also still is leaving some on the table at 15-1, it is not an all out effort as there is room to grow still. Good info here for sure. Interesting to see some of the results as well.
Posted By: AndyF
Re: torque per cube? - 01/14/10 05:28 AM
Quote:
Quote:
Thats why 440's were always perceived as torquey engines. A good amount of cubic inches with a head better suited for 350-370" engine.
Class over
Mike @MM
I think we all have taken head flow 101, Mike. What needs to be talked about more is specifics.
btw, all OEM heads back in the day were small valve, small port, except for the Hemi and the BB chev(well, the boss ford also). Take the 455 Buick, it had even smaller valves than the 440. These things made huge TQ for propelling the big Buicks down the road.
Why a big motor responds this way, tho, is still a little murkey. Is the small valve producing a faster/richer charge earlier in the RPM range resulting in more power? And is that alone producing more torque? My question i guess is: Does intake velocity account for the low RPM torque in these engines, along with the longer stroke/displacement?
Yes, the key is intake velocity. Low velocity kills the torque and so does velocity that is too high. There is a direct relationship between the CID, CSA and the RPM of the torque peak called the McFarland formula.
Mine is a small block N/A pump gas 461 cube and makes 648torque,1.405 horse/cube
Posted By: SportF
Re: torque per cube? - 01/14/10 03:32 PM
Mbogina you have good points and I agree, but maybe I stated my logic a little odd. If I go back to the mower engine that is modified with intake and carb whatever, and now it wants to no load spin to 5K instead of the 4K no load, well then we have more power, certainly torque at 4K when we didn't have any before. So overall the engine makes more power. So building an engine that wants to no load spin to say 10K, but we shift and gear it so it never goes above 7K is all better than an engine that no load revs to 8K. I guess thats my point. The "about 10%" rule is one I made up after years of noting HP and Torque figures from racers. That certainly doesn't mean all motors are that 10%. A friends nail head Buick is a good example in that it was 325 HP, but like 450 in Torque. They don't call them nail heads for nothing. SO I guess what I am saying is that typical race motors fall into the 10% rule of thumb. But its only a rule of thumb.
Posted By: moper
Re: torque per cube? - 01/14/10 04:55 PM
Quote:
Yes, the key is intake velocity. Low velocity kills the torque and so does velocity that is too high. There is a direct relationship between the CID, CSA and the RPM of the torque peak called the McFarland formula.
I believe this is one of the key elements in PipeMax's calculations too. The problem with those formulas is they give a specific number for a specific rpm. Not a range. An rpm point. IMO, fo the rpms that Greg is curious about intake pulse/wave tuning could become an effective boost too. The smallest, straightest port with the largest intake valve that isnt shrouded will make the most torque provided it's volume is correctly matched to the stroke an rpm point of the desired result.
Mike (MM), I can't recall what the constant in the HP formula represents... Can anyone answer that one?
PS - FINALLY A REAL TECH DISCUSSION!!! UN would be so happy 
Posted By: MuscleMike
Re: torque per cube? - 01/14/10 05:45 PM
It is not an easy concept to get your head around so here is an article that explains, Power, torque and the accompanying formulas.
http://www.epi-eng.com/piston_engine_technology/power_and_torque.htmMike @MM
Isn't the internet cool!