Slant Six Forum :: Holley jet

My concern is that it bogs a bit on initial acceleration.

Holley used to put a self destructive brown gasket in their OEM carbs, not the nice 'blue' gasket that comes in the rebuild kits (tha can be taken apart a few times before it's trashed...which is good for jet swaps and tuning...)

most slant guys with high vacc. readings put in a 10.5....

Correct, but the 7448 should come with the blue ones

some do and some don't... I have a 0-1848 4 barrel I purchased 2 years ago from Summit.... brown gaskets... sure made things fun when I switched it to a secondary metering block, quick change spring pod, etc...

It looks like I have the dark red (?) cam in the acc. pump. So are there basically two outside diameter jets for the Holleys and then various sized inside diameter holes? Also what secondary spring should I use. I have a mild build-up for around town quickness and reasonable highway mpg. I don't tend to speed, especially while I still have the 9" drum brakes.

Does that mean that both barrels work together like the primaries on a 4-barrel?

One other 'qualification' test does need to be made... look at the pump lever and spring that actuates the acc.pump lever... take a .020 feeler gauge, pull the throttle lever to wide open throttle... hold it there and slip the feeler gauge in between the little lever and the bolt head with the spring... if you have more than .020 on that bolt and spring... readjust it until you get the .020, then drive the car... if mis adjusted you aren't getting the proper amount acc. pump shot you need, the lever isn't getting it's full travel.

Author:	slantfin [ Sat Sep 06, 2008 2:43 pm ]
Post subject:	Holley jet
I got one of those 350 2-barrel Holley carbs from Summit. The catalog number was 0-7448. According to the Slant Six Dan: "Excuse my slip; I had thought the 2280 takes the ordinary jets like a 1920 or 1945, but in fact the 2280 takes the smaller jets." Can anyone advise on the jet size of what I have, and how to jet up a little for a higher lift cam?

Author:	Guest [ Sat Sep 06, 2008 3:18 pm ]
Post subject:
You should be able to get the jets from any autoparts store, they are cheap. Might want to check the PV while you're at it too. Just tell them you have a new 2300 series Holley...

Author:	DusterIdiot [ Sat Sep 06, 2008 3:31 pm ]
Post subject:	Ok...
0-7448, should come jetted for 61's ... you may have to go up to a 63 or so, but watch the color on your plugs... the power valve is an 8.5... depending on your vacc. readings, you may want to fiddle with that a bit... most slant guys with high vacc. readings put in a 10.5.... Holley used to put a self destructive brown gasket in their OEM carbs, not the nice 'blue' gasket that comes in the rebuild kits (tha can be taken apart a few times before it's trashed...which is good for jet swaps and tuning...) You rebuild kit number is 37-749... if you find you need a bigger 'acceleration shot' due to lean out from acceleration... you might need a bigger pump cam... we'll advise on color once you know what you need. -D.Idiot

Author:	slantfin [ Sat Sep 06, 2008 4:53 pm ]
Post subject:
Thanks. I didn't mention that I already went to a 50cc accelerator pump, just because it seemed like the American thing to do. Forget what cam I used. I am getting out the vac. gauge now, for when it stops raining. My concern is that it bogs a bit on initial acceleration.

Author:	DusterIdiot [ Sat Sep 06, 2008 8:21 pm ]
Post subject:	Er....
Quote: My concern is that it bogs a bit on initial acceleration. Now comes the question, does it bog because there is not enough fuel in your pump shot... or too much... the 50cc pump is for use with the brown cam to deliver a fair big shot (usually great for your 440...)... You might check your pump cam... if it's red or white... and the plugs color shows lean, then you will be looking at an orange cam next... -D.Idiot

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Author:	Guest [ Sat Sep 06, 2008 10:09 pm ]
Post subject:
Quote: Holley used to put a self destructive brown gasket in their OEM carbs, not the nice 'blue' gasket that comes in the rebuild kits (tha can be taken apart a few times before it's trashed...which is good for jet swaps and tuning...) Correct, but the 7448 should come with the blue ones Quote: most slant guys with high vacc. readings put in a 10.5.... DI made another great point, I put in a 9.5PV on my engine, and I may need to go higher yet. You can get these at almost any autoparts store too.

Author:	SlantSixDan [ Sat Sep 06, 2008 10:32 pm ]
Post subject:	Re: Holley jet
Just a point of clarification: My statement that you quoted was not relevant to the jet calibration (size of the hole in the jet). I was talking about the physical size of the jets.

Author:	DusterIdiot [ Sat Sep 06, 2008 10:33 pm ]
Post subject:	Not necessarily...
Quote: Correct, but the 7448 should come with the blue ones some do and some don't... I have a 0-1848 4 barrel I purchased 2 years ago from Summit.... brown gaskets... sure made things fun when I switched it to a secondary metering block, quick change spring pod, etc... -D.Idiot

Author:	Guest [ Sat Sep 06, 2008 10:55 pm ]
Post subject:
Quote: some do and some don't... I have a 0-1848 4 barrel I purchased 2 years ago from Summit.... brown gaskets... sure made things fun when I switched it to a secondary metering block, quick change spring pod, etc... Really? Facenating, thanks a ton for that info. I think when I order a new Holley 2300 for my friend next week i'll order the rebuild kit at the same time...just incase.

Author:	slantfin [ Sun Sep 07, 2008 9:20 am ]
Post subject:
It looks like I have the dark red (?) cam in the acc. pump. So are there basically two outside diameter jets for the Holleys and then various sized inside diameter holes? Also what secondary spring should I use. I have a mild build-up for around town quickness and reasonable highway mpg. I don't tend to speed, especially while I still have the 9" drum brakes.

Author:	DusterIdiot [ Sun Sep 07, 2008 9:28 am ]
Post subject:	Er...
Quote: It looks like I have the dark red (?) cam in the acc. pump. So are there basically two outside diameter jets for the Holleys and then various sized inside diameter holes? Also what secondary spring should I use. I have a mild build-up for around town quickness and reasonable highway mpg. I don't tend to speed, especially while I still have the 9" drum brakes. the jets you will be using are the saem type found in these models of Holley carbs: 2300, 4150,4160, 1920,1945...etc... the 2280 uses a system similar to the BBD, but with smaller jets than the Holley's listed above. There is no secondary spring, this is a straight 2 barrel, not a 4 barrel... Red pump cam is really little... they have 2 screw positions in the lever... switch the screw to the hole marked 2, and see what happens... if the stumble gets better... you will need to purchase an orange cam and try it again... start in the #1 hole, then move it to the #2 hole to see if things get better.... (sometimes these come as a 'kit' with various colors/profiles)... One other 'qualification' test does need to be made... look at the pump lever and spring that actuates the acc.pump lever... take a .020 feeler gauge, pull the throttle lever to wide open throttle... hold it there and slip the feeler gauge in between the little lever and the bolt head with the spring... if you have more than .020 on that bolt and spring... readjust it until you get the .020, then drive the car... if mis adjusted you aren't getting the proper amount acc. pump shot you need, the lever isn't getting it's full travel. Good Luck, -D.Idiot

Author:	slantfin [ Sun Sep 07, 2008 9:59 am ]
Post subject:
Thanks DI, I actually have the cams that came with the kit, so I may switch to the orange directly. I'll also adjust with the feeler gauge. No secondary spring, gotcha. Does that mean that both barrels work together like the primaries on a 4-barrel? I'm going to go back and read about the vacuum testing procedures that have already been covered.

Author:	DusterIdiot [ Sun Sep 07, 2008 11:01 am ]
Post subject:	Yep...
Quote: Does that mean that both barrels work together like the primaries on a 4-barrel? That's pretty much it in a nutshell... the primaries in a 4 barrel. Holley went one step further for alimited time and made a model 2305... which was a progressive 2 barrel, but the secondary plate was actuated my mechanical linkage... I think it would have been 'fun' if they had made a vacc. secondary 500 cfm 2 barrel, for 'street' use, that way it would only draw what it needed if you had a small stock engine... Say what does your user name refer to? I just had a large order of 'radiator' elements come in for a job I'm managing, and they have a big logo on the boxes that reads "SlantFin"... I oughtta save you one, so you have an official logo! good luck, -D.idiot

Author:	slantfin [ Sun Sep 07, 2008 4:47 pm ]
Post subject:
Just a bad pun on slant Barracuda. Plus I'm a contractor, so I'm always using those radiator boxes for some odd job. Just had the top down and went pretty good on the highway. Before any carb improvements. Thanks again.

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Author:	slantfin [ Sun Sep 14, 2008 12:15 pm ]
Post subject:	Re: Er...
Quote: One other 'qualification' test does need to be made... look at the pump lever and spring that actuates the acc.pump lever... take a .020 feeler gauge, pull the throttle lever to wide open throttle... hold it there and slip the feeler gauge in between the little lever and the bolt head with the spring... if you have more than .020 on that bolt and spring... readjust it until you get the .020, then drive the car... if mis adjusted you aren't getting the proper amount acc. pump shot you need, the lever isn't getting it's full travel. I'm finally getting to the carb rebuild. I'm unable to get any gap at WOT, only at the idle position of the throttle lever.