yellow rose
Overnight Sensation
There is more to making horsepower than cylinder head flow. That can’t be emphasized enough.
Disappointed magnum head flow numbers....
- Thread starter Brooks James
- Start date
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pishta
I know I'm right....
"...in order to GO, you must FLOW"...where did that come from? I think head flow is the foundation that which all power is built upon.
Ok, does this mean that mean that my set I will be making around 500 ho ?? Let’s be conservative 450 hp
Cuda416
Well-Known Member
Depends on the rest of the build.
The issue is, it doesn't matter how you build the bottom, if the heads won't flow, you're not going to make the power without an adder. If the heads flow but them bottom end isn't built to make power, well, you make more than stock but not full potential.
The engine needs to move fluids/gasses in and out. That's where the flow comes into play.
The flip side is how effective you are in;
1; Making the most power out of what you have.
2; How effective you are in utilizing that power to go fast.
1; Making the most power out of what you have.
2; How effective you are in utilizing that power to go fast.
yellow rose
Overnight Sensation
Shape is more important than flow. All day long. A quiet port that doesn’t flow well in reverse is better than a noisy port that flows 85% in reverse.
I realize that I need good
exh flow that is why I put a nitrous grind in it.
I anticipate around 500 horse on the combo with 150 shot of nitrous I was hoping I could accomplish it on stock heads
I don’t have the money for aftermarket heads that would definitely do the job
I jus want an estimate nothing is chiseled in stone
360 mag
Stock block/ heads/ crank/rods/ 9:1 pistons
Edelbrock knock off airgap
MSD 6al my dizzy accel super coi904 w: 3500 converter
Massaged 750 dp
You already the specs on the cam engine is not that far off 380 crate
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- flow at low lift is important
- matching the rest of the car to the engine is important
- having the car "work" in itself is huge.
Bingo dead on.
Exactly what I was saying above.
yellow rose
Overnight Sensation
Point one is not what my experience says. For more than one reason. I look at the numbers below about .200 lift, but unless something is way wrong I don’t care about that.
If you can test low lift at say...100 inches of water you’d see why the low lift numbers don’t mean much at 28 inches. Plus, the piston is in the way. Plus, you have to deal with cross flow at overlap. To fix that you have to reduce overlap and that’s a power killer.
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I should have said what I meant at low lift. .400
With a 150 shot 500 hp should not be difficult to hit with magnum heads.
jos51700
Green Bearing thread connoisseur
Listen, comparing flow numbers you found on the internet is like writing food reviews by reading the menu.
#1 no two flow benches are the same.
#2 no two operators are the same.
#3 no two weather conditions are the same, and this matters because flow machines do not suck, they cause atmospheric pressure to blow.
Notice I didn't even get into heads, valves, cam dynamics, etc. If you're reading flow numbers on the internet trying to decide what heads are best, you're not driving at a level that it will matter.
#1 no two flow benches are the same.
#2 no two operators are the same.
#3 no two weather conditions are the same, and this matters because flow machines do not suck, they cause atmospheric pressure to blow.
Notice I didn't even get into heads, valves, cam dynamics, etc. If you're reading flow numbers on the internet trying to decide what heads are best, you're not driving at a level that it will matter.
K.O. SWINGER
Meeting in the alley since 1976
Horsepower on a nitrous boosted motor at the kind of power level you're talking about is primarily affected by nitrous jetting. The Magnum head has a decent exhaust side which will help accommodate the nitrous. Head flow becomes a little less critical factor when injecting torque from a bottle. I personally wouldn't spend a lot of time on a set of Magnum heads unless you just love them. if you're going to upgrade then step up. But that being said 500 horse range is definitely achievable with Magnum heads on the juice.
Thanks, I did a lot of research to set this up. I figured that what I have now is close to the level of hp I could make without spending a lot more and keep from blowing the motor. I will be able to have lots of fun with 500 hp on the
street, when I get traction set up. Off the juice it will be a 13 sec mild plus engine which my wife can still drive to the grocery store which is exactly what I want. and hopefully in the high 11’s on the juice, which I consider to be a respectable in a daily driver. It will be like what Hirohito said when the japs destroyed Pearl Harbor “I keel as if we have awakend a sleeping giant.”
street, when I get traction set up. Off the juice it will be a 13 sec mild plus engine which my wife can still drive to the grocery store which is exactly what I want. and hopefully in the high 11’s on the juice, which I consider to be a respectable in a daily driver. It will be like what Hirohito said when the japs destroyed Pearl Harbor “I keel as if we have awakend a sleeping giant.”
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Just for comparison my 470 stroker Dynoe’d at 655 hp. Heads flow 320 cfm. I believe the formula is 2.06 hp per cfm. Mine is actually pretty dam close. Volumetric efficiency was 108%. I will add that some motors put out beyond expectations while others fall short. I can’t stress cylinder prep enough. Having straight round bores is an absolute must. Kim
I can give you some track numbers if it helps on my '71 Cuda with stock 340 motor, 2.02 non ported heads that are around 215cfm@best+HS dom intake, 850DP, .590"DC sft cam, 4200stall etc. etc. Motor only made 367fwhp, best mph was 108 NA, according to weight/mph. Added a 250shot but only got actual 158hp from it (525) for other reasons like too rich petrol jet specs back then (110n/110p) and not enough backed off timing but ran 122mph. So you can do it on stock heads, you should be able to get almost 150hp from a 150 shot if you tune it well with todays jettings etc., and your motor is up there with NA hp.
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OK 220 x 2 is 440 hp normally aspirated
How much more. Hp can i expect with a
150
Shot of gas
What about 220 flow x 2 is 440hp, what about a 150shot of gas added
gzig5
Well-Known Member
Ok, I'll play along.
440+150=590
OK my build is based on the 360/380 crate, which i have read that regularly dyno at 400 hp, im hoping 530 hp and 500 torque, does that sound reasonable ?
Krooser
Building Chinese Free Engines since 1959...
I doubt it.
My 388" 360 based race motor started life with ported w-2 heads flowing 294 cfm intake, 13-1 compression on alky, 750 Holley DP, dizzy locked at 36 degrees, Crower solid lifter cam 580/580 with a 260 degrees duration @ .050... 575 HP @ 6,000 rpm.
Now I'm shooting for 625 with my 850 carb, more cubes, lighter valves and a better cam. Still might not make it...
33IMP
Well-Known Member
I think he is including a 150 shot in those numbers.
Krooser
Building Chinese Free Engines since 1959...
Makes sense...
Go to Hughes Engines website. They have flow data from all kinds of heads on there.
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