OFFY DUAL 1BBL Intake question

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yooper822

yooper822

Joe Roberts
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So I'm putting this Dual 1bbl intake together for my 66 cuda and the directions say to use jets 2 sizes smaller than stock. Is it even possible to find these any more? What is the consequence of not using the smaller jets?
joe
 
yooper822 said:
So I'm putting this Dual 1bbl intake together for my 66 cuda and the directions say to use jets 2 sizes smaller than stock. Is it even possible to find these any more? What is the consequence of not using the smaller jets?
joe
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Hey retired Navy,

Retired army here. Just got mine running today. I don't see anything wrong with running the stock jets given that these motors tend to run on the lean side.
 
If it really does come down to it and you can not find jets and you absolutely need different ones you can always solder them shut and then redrill to the size you need. I am putting a bendix stromberg 2bbl carb on my slant and will likely have to do this procedure to it. You will need a good set of numbered wire size drill bits and some time.
 
I've only seen a couple of sizes that holley has(therer may be many more but I've only seen those 2 sizes for a long time. I think it's either 6-32 or 1/4- 32 sizes . Open it up and measure it. I've seen both sizes on summit racing. I'm doing the same conversion and just got the linkage to the carbs done. haven't got to the jetting yet,so I'm no help there. but I will be looking for jets to change mine out.

and if I can't find them I will have a gunsmith friend of mine solder and drill mine.
 
Yeah you're gunna have to re jet. Definitely getting the gas smell it's running rich. I put mine on a month ago and it does great other than running very rich
 
The Holley 1920 one barrel carb uses the same jets as the Holley 4 barrel carbs. Just order the correct size, they usually come in packs of two.
 
Charrlie_S said:
The Holley 1920 one barrel carb uses the same jets as the Holley 4 barrel carbs. Just order the correct size, they usually come in packs of two.
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cool thanks
I've got a holley jet kit in my friends shop up north where I do all his cars. I'll drag the manifold up there and play with it.
 
You may not have small enough jets in the jet kit. The 1920 had jet sizes in the mid 50's if I remember correctly. I think around 53-55
 
Charrlie_S said:
You may not have small enough jets in the jet kit. The 1920 had jet sizes in the mid 50's if I remember correctly. I think around 53-55
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55 thru 64 jets depending on year...

to the OP

Ted, a guy on .org is getting his best mpg with a 57 jet. if i were you i would start with a 55 and see what happens. just keep jetting down 2 at a time till it surges.

i would buy 55's and 53's to start. if the 55 dosn't surge try the 53's...

also back off the accel pump, you will see the control arm on the valve cover side of the carbs, move the linkage to the lowest hole, that will back off the pump shot.
 
I know this is an OLD thread , but would like to know what size jets worked the best , I am running rich , thinking of going down in size
 
Most of this thread discusses the holley 1 bbl and the concensus seems to be #53 or #55 Though one post referenced a car on /6.org using a #57 with good success. If you don't have holley one barrels and are using the carters you will be hard pressed to find replacement jets. There really is no ideal jet size due to many factors affecting fuel usage like header vs stock exhaust, cam choice, rear end gears, etc. If you have the holley carbs pull a float bowl remove the jet and buy 2 sizes smaller. Still to rich?, repeat process until as another poster suggests, you feel a hesitation at cruise. This is to lean. From this point go up one or two sizes.
 
Thanks , Yes they are 1920 , jets are 55 - yes headers mild cam 4 speed factory , and original rear , 225 is .40 over , all was done prior to me , but have receipts from machine shop. I have rebuilt the 1920 's and changed it over to electronic , fires right up , but still smells rich , always has from the time I got it , and wants to stall from a dead stop. vacuum is at 19 on both of them with gauge plugged in to bottom of carb where choke pull off is . plugs looked rich to me , but I am a novice.
 
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The problem of to rich at idle and an acceleration stumble may not be related. The stumble off idle is more often associated with a mis-adjusted/malfunctioning accelerator pump. Your holley's have an accelerator pump diaphram in the float bowl with an arm that sticks out and connects/rides on a plastic rocker piece. The opposite end of this plastic arm is directly linked to your throttle linkage. Check that when you move the throttle linkage that the accelerator pump arm I'm referring to moves (in I believe but it's been awhile) and initiates a fuel squirt.
 
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