Carb Selection

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Cazbah362

Cazbah362

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Folks, need some input and suggestions. Here is the setup. 71 Dart factory weight, 430 gears, 295/65/15's, 3000 convertor, 440 .30 over, quench pistons, 484 cam, 906 heads, M1, HEI ignition, I live at 5000 alt, raceway is 4000.

Right now I have a 750 vac secondary with Proform main body. 75 primaries and plate (would assume 70). Had 67 Jets, updated to 75. At about 4800 starts to fall flat like fuel issue. I have 7lbs fuel pressure through 1/2 p/u and 3/8 return. I dynoed the motor and 425 hp, pulled good no issues with mechanical 850 jetted 84/84. (Not my carb, was shop mule carb).

First, should I try to update my 750? with QF plate, secondary 78 jets and possibly spring changes for rate of opening?

I have been looking at the Holley 850 (http://www.summitracing.com/parts/hly-0-80804bk)

Or

QF: http://www.summitracing.com/parts/qft-bdq-850

Or do you have ideas, thoughts
 
At top gun raceway, the corrected elevation the pass two summers I raced up there was over 6000 ft....

I leaned out the holley 950 by 4 jets in the primary and secondary while racing up there..

and the 750 dp on my friend 410 small block was 72 p and 80 secondary with no power valve.

just saying ...dont get jet happy...
 
Tony - Thanks, 67 was too lean, had a bad needle/seat issue so with other changes figured I would plus up a bit, yea swag. Did an HEI conversion so I am trying to baseline with this changes. Would like to head over to Sac for a grudge night. Are you coming up over the summer again?
 
Hopefully ...NOT...lol

But you never know...lol, We might get some work up at South Lake Tahoe...if we do..I volunteered for that...

We went to Sacto for the Mopar Race in Sept...nice to get to sea level...ran 6 tenth faster there then Top Gun...but Top Gun is fun...no hassle, small track....hope everyone comes out and supports it.
 
Well-as a newbie, I'm going and learning at both as much as possible. Top Gun is a little easier for learning, just high. Races this weekend so trying to iron out some bugs, wishnthey had more t&t.
 
Top Gun,such a hidden racetrack. I love the track,the location. Damn basic,as it gets. Hate the elevation. The most basic track,I have ever seen.(To me,a good thing.).
 
I will probably show up there for a weekend race .....later in the year.....
 
Agree on basic being a good thing -

Anyone have insight for me on this? or am I on focus?
 
I've seen people have great success with the 950 HP.
 
I think proform suggest a 72 primary main jet as a baseline for that main body. I'd run something in the 68-70 range at your altitude.

If running the std 134-21 rear plate, it's basically a 75 main jet. So that side may be slightly fat. Look at the quickfuel 34-3 plate if you want some adjustability using std main jets.

sept1012.jpg


Get a notched float if running the QFT plate.
 
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