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-   -   darts new 380 for bbc? (https://www.racingjunk.com/forums/showthread.php?t=18197)

deepockets 08-27-2007 05:50 AM

darts new 380 for bbc?
 
dart has a upgraded from it's 355 rect port 24 degree bbc head. any pro's or con's on it in the power department. 565 ci 14.5 comp 800+ cam 7-4 swap 1150 holley. it's for all out drag racing. just wondering if any of you engine guys have any hands on yey or opinions

excelerater 08-27-2007 03:07 PM

I havent heard about it but
everyones just keeping up with the jones's
and in this case a BMF385 I would guess

cboggs 08-27-2007 09:20 PM


Originally Posted by excelerater
I havent heard about it but
everyones just keeping up with the jones's
and in this case a BMF385 I would guess

wrong, .. there's much better conventional style BBC heads available, ..

Dart does a CnC version based on their 360 race casting that is
a VERY, Very good head but it doesn't get the press some others do, ..
it's also the fastest head in Texas pro stock right now, ..

Edelbrock Victor 24* with it's moved valve locations is a REALLY
good head when properly ported, . . likely make more power then any, ..
Long thread over on Speedtalk about all the testing Larry Meuax did with
it, .. well over 1000 hp.

Brodix BB-3x is a great casting and also makes some serious power
when properly ported.

At any rate on the original question,.. I haven't seen a set yet, ..
but it would be my guess it's not an "upgrade" of the 355 per say
but likely a new Port offering.

The difference between 355cc port and 380cc port would be rather
large in the ports' Cross sectional area, .. and that sets air speed.
The cross sectional area and air speed are really how heads are designed
much more then just flow numbers, .. and the air speed gets matched
to the intended application.

My guess would be the 380 cc port has a cross section around 3.8 -3.9"
and that would make it designed for a 565" to around 598"

are you running a dragster or light car?

Curtis

deepockets 08-28-2007 06:00 AM

it's a door slammer, weighs 2910 with me in it, glide and 4.86 or 4.56 rear and 33 inch tire, thanks for the in depth request, the engine builder located in new your claims that the 380 picked up power across the board from going from the 355 dart to the enlarged 380 cnc.

cboggs 08-28-2007 03:57 PM


Originally Posted by deepockets
it's a door slammer, weighs 2910 with me in it, glide and 4.86 or 4.56 rear and 33 inch tire, thanks for the in depth request, the engine builder located in new your claims that the 380 picked up power across the board from going from the 355 dart to the enlarged 380 cnc.

Perhaps there was a power gain in that builder's application but it's
not that simple.

The head has to be matched to your application, . . and by just
sticking a bigger head on the motor could slow the car down
even if it showed a power gain on the dyno.

The key is the air speed in the port, .. when it getts to big it'll
get lazy, won't 60' as well and not recover well off the shift.
It might put up a big number on the dyno but in the case of
a 3000 lb car very easily could be slower on the track.

Personally I think if you are turning your engine as hard as a typical
bracket style engine, maybe shift 6800, 7000, . . then it's likely
you have the right head now, ..
I'll ask my guy at Dart when I speak to him tomorrow
what the cross sectional are is in the 380 cnc.

how much power do you make now?

Cheers,

Curtis

deepockets 08-28-2007 05:18 PM

the motor is being ordered from shaffiroff, it's suppose to be at a thousand h/p. that was with the 355 cnc darts. now they said they are useing only the 380 cnc dart. i can go one or the other and since it's a new port size i can only go by what they say, thanks again for all your guys help

hammertime 08-28-2007 06:32 PM

save your money call RM

been there done that ......

cboggs 08-28-2007 09:03 PM


Originally Posted by hammertime
save your money call RM

yea I would agree, ..

BTW hammetime, .. love the paint on your car, ..

Curtis

hammertime 08-28-2007 10:04 PM

thanks Curtis :D

one of them so called 1000hp motors SSRE put together for a friend of mine ran a tenths slower then my little small block that might of made 700hp and his car was lighter. It did make it 1/2 a season before it broke a push rod to take it apart and find out a lot of wrong parts. My 434 i got from them lasted 16 passes before breaking a oil pump which they'd never heard of a small block doing before. :roll:

Pwmax 08-29-2007 04:45 AM

I can give you an example of what Curtis is talking about, when you just chase flow numbers, and the head is to big for the combo. A local guy, that is a friend of a friend, that chooses for some reason, to keep going back to a local head shop, recently revamped his combo. 496 cubes, 4.310 bore, Brodix BB-2plus heads, had 13.5 ish compression, 280ish .800 lift cam, etc, car ran 10.00's at 137 on a good day. The shop put in 2.35 intakes, ported the heads to 369cc, and they flowed 420, bumped the compression to 15:1, put in a 296-304 at .050, yes, at .050, .880 lift cam, and the engine picked up about 60-70hp. The car, runs exactly the same et and mph as before, and is described as "lazy". Plus, he has the added benefit of spinning the engine 8000 rpm too. It actualy ran slower the first time out, but after a new converter and more gear and 600 more rpm, it runs the same as before.


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