BIG DUKE VS BIG BRODIE

Old 05-12-2008, 11:55 PM
  #1  
jrthone
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Default BIG DUKE VS BIG BRODIE

BATTLE OF THE BRODIX

If a Big Duke can flow 440cfm @ 0.800"out of the box and a Big Brodie(say BP BB3 Xtra-O etc) can flow [email protected]" with ease with still lots of room to go further. Why go to the expense of 18-12 degree heads
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Old 05-13-2008, 12:03 AM
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cboggs
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because a well ported big duke will flow more then that, ..

BUT, it's not all just flow, .. the raised runner of the big duke allows
better delivery to the valve, better fuel delivery into the chamber, .
and well ported will flow well over 500 cfm.

typically a spread port head like the big duke will make at least 60 hp
more then a conventional head, ..

other consideration is average power not just peak, .. average power is
what really makes et and fast cars on the track, not just peak power.

Curtis
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Old 05-13-2008, 12:36 AM
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jrthone
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But a well ported BP BB3xtra-O will flow more than 500cfm as well. Is it really worth the expense in say a 1200hp big block.Maybe up around the higer mark but surly there nothing wrong with running the BP BB3 XtraOs on a 1200hp Big Block.
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Old 05-13-2008, 12:37 AM
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jrthone
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Im only arguing this point because racers on a budget need somthing good to work with especially with 600+cubes. Is it really that bad to run BB3 xtras?????
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Old 05-13-2008, 06:01 AM
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cboggs
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Originally Posted by jrthone
But a well ported BP BB3xtra-O will flow more than 500cfm as well. Is it really worth the expense in say a 1200hp big block.Maybe up around the higer mark but surly there nothing wrong with running the BP BB3 XtraOs on a 1200hp Big Block.
I don't know who told you a bb3 will flow more then 500 cfm, but that is total BS, .
460 maybe 465 cfm max on an honest bench, . .. plus the head is too small
for a large cube engine.
Can't get the area for a 600" engine out of an oval port conventional head , ..

If you're on a budget yes it's a fine head but won't make 1200 hp.
There's a hand full of good conventional heads for a 600" engine.
Dart's big M is a 410 cc port conventional and when well ported with a big
valve will flow over 470, .. and has made great power for years.
We do a large port version of the Victor that flows over 470.
BMF has a 400 cc head that will make good power with some work.

Keep in mind peak flow isn't the only thing that makes power.


Curtis
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Old 05-13-2008, 06:15 AM
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wltrb
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I remember a guy who had a dragster with a Sonny's motor in it with Dart bigm's, .. and a single 4, .. ran 6.80's back in the early 90's, ..

w
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Old 05-13-2008, 12:12 PM
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jrthone
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So if they come out of the box flowing 461cfm.You are telling me you cant get another 39cfm out of them.
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Old 05-13-2008, 01:06 PM
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bbchevy
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Default Budget?

Budget???
Can we switch Budgets?You will have more in your Heads then i will have i my Whole Long Block!
My Opinion,if your after 1200HP and worried about your Budget?Then somethings is Wat Wrong withe Picture?
If Curtis tells you a Quarter is only Worth a Dime?LISTEN to HIM!He will Explain WHY...................?
Later
G 8)
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Old 05-13-2008, 02:15 PM
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hammertime
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Originally Posted by cboggs
Originally Posted by jrthone
But a well ported BP BB3xtra-O will flow more than 500cfm as well. Is it really worth the expense in say a 1200hp big block.Maybe up around the higer mark but surly there nothing wrong with running the BP BB3 XtraOs on a 1200hp Big Block.
I don't know who told you a bb3 will flow more then 500 cfm, but that is total BS, .
460 maybe 465 cfm max on an honest bench, . .. plus the head is too small
for a large cube engine.
Can't get the area for a 600" engine out of an oval port conventional head , ..

If you're on a budget yes it's a fine head but won't make 1200 hp.
There's a hand full of good conventional heads for a 600" engine.
Dart's big M is a 410 cc port conventional and when well ported with a big
valve will flow over 470, .. and has made great power for years.
We do a large port version of the Victor that flows over 470.
BMF has a 400 cc head that will make good power with some work.

Keep in mind peak flow isn't the only thing that makes power.


Curtis
No doubt Curtis is right never seen a bb3 oval over 500 or even close to it, a brodix big duke IMO is awesome head.
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Old 05-13-2008, 10:56 PM
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cboggs
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jrthone,

I think you're missing the point, .. more flow doesn't mean more power, ..
it's just not that simple.
If it was we could just put a 2.8" valve in a 600cc port and flow 1000 cfm, ..
but we both know that wouldn't work.

We have to consider air speed BEFORE the mass airflow volume or CFM.
If you don't have proper airspeeds you will never fill the cylinder over 100%
that is necessary to make the power levels we are discussing.

Exit speed of the intake charge out of the valve and into the chamber is one of
THE most important design issues to making good power.
Slow, sluggish air speed and power drops off fast.

So, .. this being said there is actually a fine balance between the mass flow or
CFM of a head designed for an application, .. and the airspeed or velocity that
head is designed to produce.

Big holes make big cfm numbers that look good in magazine ads but don't
run well on the race track. So that being said, yes I could likely make a -3 flow
another 39cfm, .. and it likely wouldn't run worth a crap on a typical bracket engine.

Case in point, .. I know of a head that was advertised at over 500 cfm, ..
and actually did it on a good bench, .. and makes less power then my standard
RFD / Victor or an out of the box -3, .. by a bunch.

David, .. I love the 1803 big duke, .. damn nice head.

Curtis
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