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Jets for stock carb 4.8

Old 02-21-2019, 07:16 AM
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Default Jets for stock carb 4.8

I've got a a stock 4.8 with a Holley single plane and a Holley 600 double pumper probably not the ideal set up but it's what I had. It's got 73s in the primary and 66s on the secondary right now, any idea where it start off for jets?
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Old 02-21-2019, 11:07 AM
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How does it run now?
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Old 02-21-2019, 03:21 PM
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Sure those numbers aren't backwards ?

I would start with what you have as said above.

My best purchase was an AFR meter....tune with out pulling plugs and all the testing. Dialed in my carb quick and easy
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Old 02-22-2019, 04:25 AM
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Usually the secondary jets are bigger than the primary. The primary has a power valve

For a starting baseline I would first search the carb stickies to see if anyone posted a carb like you have and clone that

If no luck find your carb number in the listing below and start with a stock baseline.

Carb might be a touch small but otherwise nothing wrong with your set up.

And a wide band O2 is money well spent. You will be guessing on your carb set up otherwise
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Old 02-22-2019, 09:03 AM
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I've only run it for a second because there's no cooling system on it yet but it didn't really idle but it was also cold and floats not set up etc.., I just fired it to make sure it started. And yes I'm sure on those jets, I just rebuilt the carb and put them back where I got them. So you think I should swap the bigger ones to the secondaries?
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Old 02-22-2019, 09:09 AM
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Just looked it up they are stock jet sizes but yes they are backwords. Also what timing should I be running? I'm unsure what it's at now as I'm having trouble getting a computer to connect to the msd box
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