Sounds like we should both buy a Hurricane so we can get higher vacuum. Just need to figure out how to heat it.....the snow is deep out my way and it's been real cold.
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| Carb cfm and primary sizing https://www.slantsix.org/forum/viewtopic.php?t=33134 |
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| Author: | Aggressive Ted [ Sat Jan 03, 2009 11:30 pm ] |
| Post subject: | Carb cfm and primary sizing |
I just went through all my Holley books and all my sons. I wish Holley would rate the CFM for the primaries for their carbs, 2300 series 350 2V verses the 390 4V. How much smaller in diameter are the 390 primaries? or are they the same as the 2V? Anybody have both carbs handy to measure? or have any CFM rating data? On the Holley 390, does the front have a different CFM rating than the rear? Thanks! |
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| Author: | 68barracuda [ Sun Jan 04, 2009 1:10 am ] |
| Post subject: | |
hi Ted cant remember the figures but the chokes and throttle plates for the 390 4v are the same |
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| Author: | emsvitil [ Sun Jan 04, 2009 1:21 am ] |
| Post subject: | |
A little less than half if it's not a spreadbore.... Don't forget that 2bbl and 4bbl ratings are at 3inHg and 1.5inHg respectively....... |
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| Author: | rock [ Sun Jan 04, 2009 8:52 am ] |
| Post subject: | Ted, I have several of each and here is my measurements |
Hi Ted, Merry new Year! I understand your question to ask first, what diam's can someone measure in 2300's and the 4bbl 390 cfm series Holleys. I have several of each stuck away for "someday" so went out and put a mic to em. The 8007 390 cfm 4160's I have are all squarebores at 1 7/16 primary diam (not venturi diam). (I changed mine to 4150's by adding a 2dary metering block to each, but that doesn't affect the throttle body or main block.) I have three different number 2300's and I had forgotten that I thought I had just picked up three 2bbls! I have the 300 cfm, the 350 cfm, and the supposed 490 cfm models. All three have 1 1/2 inch throttle bores. I also have a list I got long ago from Holley that is old enough to have the R- designation of carb numbers, and of course my carbs are R designated. I am NO Holley expert but I remember that Holley made 2300 2bbls in a wide range of cfm, but I have only the 300 to 500 cfm range to measure so have no knowledge of any other variation of primary diam in any others, but I didn't consider any others as being slant size size. Since you asked what is interesting to me is that there is a design with only a 1/16 diam difference. It emphasizes what you, Dan,and Reed say about how well the 2bbl will feed a slant and that you don't HAVE to run the 4160 series. I never tried the 2bbls but sure like the 4! Hope this helps, rock '64d100 |
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| Author: | Aggressive Ted [ Sun Jan 04, 2009 9:06 am ] |
| Post subject: | |
Rock, Thanks for taking time to look them over and doing the measurements. That is what I wanted to know. What kind of vacuum readings do you see with the 390? at idle in and out of gear? |
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| Author: | DusterIdiot [ Sun Jan 04, 2009 9:24 am ] |
| Post subject: | What book do you have? |
Quote: I wish Holley would rate the CFM for the primaries for their carbs, 2300 series 350 2V verses the 390 4V.
Your vacc. reading will depend on a lot of factors and your build... I get 26" vacc. out of the hpak duster at idle, and 21" at cruise on the flats with a 390 cfm 0-8007, it dips to 17-15 when taking hills or passing...How much smaller in diameter are the 390 primaries? or are they the same as the 2V? Anybody have both carbs handy to measure? or have any CFM rating data? On the Holley 390, does the front have a different CFM rating than the rear? If you have the old Blue Holley book by Dave Emmanuel, it will list the primary and secondary bore sizes, venturi sizes, etc. in the carb chart... that will give you an idea of how much one set of primaries will flow compared to the other carbs. Holley used to have an update chart on their website for download, also.. Holley 7448 uses a 1 1/2" throttle bore with a 1 3/16" venturi. Holley 8007 primaries and secondaries are both 1 7/16" bore with 1 1/16" venturi So the primary side of the 8007 will flow sightly less than the 7448, so if you choose your secondary spring correctly it will have about the same or better gas mileage than the 350 fm 2 barrel, but have more flow available if you need to pass with extreme prejudice... Compare that to the 80120 that Reed had sold me a while back which has the 1 11/16" bores and a 1 3/16" venturi...pretty major drop between the two numbers... good luck, -D.Idiot |
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| Author: | 68barracuda [ Sun Jan 04, 2009 10:00 am ] |
| Post subject: | |
DI I agree !! |
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| Author: | Aggressive Ted [ Sun Jan 04, 2009 11:16 am ] |
| Post subject: | |
DI, Very good info. thanks! That is some really good vacuum compared to my build with the 1920. At idle I am at 18" out of gear and 16.5" in gear, cruise is 12 to 16". When I left off on the gas it will hit 23" max. I am looking forward to doing the swap to see how high the vacuum comes up. As you know I built mine for torque and mileage. I am hoping the Weiand will help with the low end torque. It would be nice to run a longer manifold, but I need the heat. Sounds like the 390 is the way to go. My son wants me to chase him down the strip this year, so the 390 4V should help with the mileage and provide a little more umph when needed at the strip. What kind of economy can you get with yours? |
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| Author: | rock [ Mon Jan 05, 2009 5:01 am ] |
| Post subject: | Ted, my vac. isn't like Rob's |
Ted, My vac with the 390 cfm 8007 is pretty close to what you are reporting with your 2300. Idle about 17 -18 in P, about 15 -16 in D, cruise about 16 - 20, and drop to 5 - 12 under acceleration. Course this is a 3.91 rear end with a 727. Plenty of power because I built for low end torque. rock '64d100 |
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| Author: | Aggressive Ted [ Mon Jan 05, 2009 8:40 am ] |
| Post subject: | |
Sounds like we should both buy a Hurricane so we can get higher vacuum. Just need to figure out how to heat it.....the snow is deep out my way and it's been real cold.
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| Author: | DusterIdiot [ Mon Jan 05, 2009 5:59 pm ] |
| Post subject: | Look at the old Hpak threads... |
Quote: Just need to figure out how to heat it.....
Do a search for Dusteridiot and 'Hpak'.. there is a thread with pictures of the exhaust fed underplenum heaterbox... once you dial in your carb it should be turn key an go in most weather (but a bit cranky in very low temps --like 20 something or less...when carb icing is the worst...)-D.Idiot |
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| Author: | kesteb [ Mon Jan 05, 2009 10:32 pm ] |
| Post subject: | |
As I have said before, Ford made some real nice water heated base plates for their 2 and 4v carbs. They should take care of any "heat" problems. |
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| Author: | wjajr [ Tue Jan 06, 2009 4:27 am ] |
| Post subject: | |
Brent67Cuda904: Quote: Your vacc. reading will depend on a lot of factors and your build... I get 26" vacc. out of the hpak duster at idle, and 21" at cruise on the flats with a 390 cfm 0-8007, it dips to 17-15 when taking hills or passing... I suspect that cam shaft selection has more bearing on vacuum than carburetor choice. I have a 0-8007 Holley, unknown Erson cam,Clifford intake, with 3.55:1 rear axel ratio, and can only pull around 15 Hg on flat ground 35-70 mph, at idle 850 rpm 13 Hg in P, 8 hg 650 rpm in D. What is your cam shaft grind? |
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| Author: | DusterIdiot [ Tue Jan 06, 2009 5:33 am ] |
| Post subject: | But... |
Quote: As I have said before, Ford made some real nice water heated base plates for their 2 and 4v carbs. They should take care of any "heat" problems.
That's great if he goes for the short ram, but he said the magic word 'hurricane'... when you slide the carb toward the side of the car...you limit the room you have for the air cleaner to hood clearance... a half an inch plate can make a big difference in whether to cut or not cut your hood... the hurricane is a bit shorter than the hpak manifold luckilyKeep in mind most areas now, do not keep carbed vehicles in their yards for long...all junkyards in my area now crush any pre-1985 cars outright as they don't bring in the money that a more common late 80's early 90's car would. -D.Idiot |
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| Author: | Rug_Trucker [ Tue Jan 06, 2009 6:36 am ] |
| Post subject: | |
repost |
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