Holley Street Dominator vs '73 Cast intake

street dominator or factory cast?

  • Holley Street Dominator will improve the performance

    Votes: 10 41.7%

  • Factory Cast intake is just better... especially for this car

    Votes: 9 37.5%

  • won't see a difference either way.....

    Votes: 1 4.2%

  • I have no idea...

    Votes: 4 16.7%
  • Total voters
    24
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Funny how things work out....

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I'll guess you have something going on with jetting or fuel delivery.
 
crackedback said:
I'll guess you have something going on with jetting or fuel delivery.
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yeah, I didn't do anything but drop the carb on both intakes. Could be that it was, by chance, better tuned for the cast. I know with more runs I could have played with it and somewhere picked up 8 hundredths of a second to match the 14.95 time, but I don't think on this day I was going to get my 2.3 mph back.
 
nm9stheham said:
Weather differences?
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I think both days temp and humidity were good. I did have a "slight" head wind with the SD, but it seemed most racers were running the same MPH. No way to ever get it perfect, not even on the same day as time changes the condition. I think the days were very comparable.
I knew they would be very close, and they were. I just figured if any difference in the quickness, it would favor the cast (especially with the SD having the 1 inch open spacer), and any difference in mph might favor the SD. Funny how it went opposite.....
  • side note: I had just a little less than a 1/2 tank of gas on both days
 
I ran a Holley SD on my 351-C powered dirt car for two years...great performer up to my self imposed 6000 rpm redline...
 
Krooser said:
I ran a Holley SD on my 351-C powered dirt car for two years...great performer up to my self imposed 6000 rpm redline...
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Keep in mind, each SD is majorly designed differently per different engines. The small block mopar SD has ports smaller than the eddy performer and weiand action plus, and absolutely no bigger than a 273/318 heads. If you look at the gasket match markings in the pictures I posted above, them were with the 318 gasket. This particular intake was really meant to stay under 5000.
 
I think you need to tune the carb the same as the stock manifold then decide which one is better.
In other words, post up on this thread next year after you have had good and bad race days, carb is as happy as it was before.
The SD sure looks promising.........and really was intended for the eng combo that you have.
I sure would have guested, w/2.76 gears, 60 foot would have when down not up.........Nice threads Thank You!
 
No thread derail intended but, I've heard you can use (should use?) a smaller carb on a single plane because the large open plenum lessens the vacuum signal that the carb sees. Just thinkin' out loud.
 
YoloCtyFlash said:
No thread derail intended but, I've heard you can use (should use?) a smaller carb on a single plane because the large open plenum lessens the vacuum signal that the carb sees. Just thinkin' out loud.
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I like to say dual planes use a 100 cfm's more.... :) IF a carb is too big, it's usually off line that is slowed, and in my case it's where I picked up. Also, the SD intake isn't the "normal" single plane intake. Big plenum and small runners, it's designed for 318's and the street.
 
YoloCtyFlash said:
No thread derail intended but, I've heard you can use (should use?) a smaller carb on a single plane because the large open plenum lessens the vacuum signal that the carb sees. Just thinkin' out loud.
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I'm not seeing that being the case..... airflow is the same, and carb restrictions are the same. Sounds like some mixed info, or a cause-and-effect that is being attributed to the wrong thing.
 
nm9stheham said:
I'm not seeing that being the case..... airflow is the same, and carb restrictions are the same. Sounds like some mixed info, or a cause-and-effect that is being attributed to the wrong thing.
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The article (wish I still had it) made sense to me, but I know I won't be able to explain it in text. How about this; If you knew you had a perfectly sized carb on an engine with a dual plane intake, and wanted to try a single plane, are you certain your carb is still the perfect size? (adj. and jetting aside) Not arguing, just asking.
 
I like the SD. It looks better.......and its almost a wash? Look at your weight savings and coolness factor. Wonder if there is a mileage change?
 
pishta said:
I like the SD. It looks better.......and its almost a wash? Look at your weight savings and coolness factor. Wonder if there is a mileage change?
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If I ground down the unused mount, I could ditch the 1 inch spacer. I'm positive if I do a little tune/test, there would be a little more somewhere, someplace with the SD.
 
Street Dominator,.. please. Just the fact it is so close to a factory dual plane,with improvement to work with. I bet it wants more initial timing,more primary jet. Just my grassroots tuning thought
 
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