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Tuning Holley 1bbl for 7500 feet, Are 4bbl jets the same?
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Author:  Guest [ Mon Nov 10, 2003 12:31 pm ]
Post subject:  Tuning Holley 1bbl for 7500 feet, Are 4bbl jets the same?
I just moved to 7500 feet above sea level this weekend. The Holley 1bbl is rebuilt and tuned for sea level. It runs strong and gets 22 mpg at sea level. Up here its a dog and needs to be rejetted badly. I have one of the holley jet kits for their 4 bbl carbs, but I haven't had a chance to open up the 1 bbl to see if the jets are the same or even what size jet I have. Anyone know if these jets are the same? Due to a parking nightmare I need to be able to remove, rejet, and reinstall the carb in 3 or 4 hours. So I need to have all parts on hand before I start. If anyone has some educated guesses on jet size to get me in the ballpark I would be greatful. I know I'm not going to get all my power back but with the huge gap between 2nd and 3rd gears I need all the power I can get. Thanks, Mark

69 Plymouth Valiant 100, 4dr
225 with a 1bbl Holley carb
mildly ported '74 head
3 on tree manual trans
electronic ignition: stock distributor, an accel coil and a generic orange box
10 deg BTDC at idle
dual field alternator
nippondenso starter (88 cop car) and an optima battery
stock cam, compression and exhaust
Author:  Reed [ Mon Nov 10, 2003 1:27 pm ]
Post subject: 
Yep. THe jets mwill be the same as a Holley four barrel.

Reed 8)
Author:  Guest [ Mon Nov 10, 2003 4:35 pm ]
Post subject: 
Howdy -
I just rejetted a 4bbl holley for Colorado Springs, 6600 ft. The recommendation Holley makes is pretty close - one jet size smaller for every 2,000 ft. altitude. The Holley had 51's in it, I put 49's in it and it ran nicely but the plugs were running blackish. I had a smog check with the 49's and failed. I took the results to the local hot rod shop and he said go to the 47's. I did, and passed with flying colors (the '73 Dart /6 only has 50K miles). I think it now runs a bit lean, and 48's may be right on.
This was done on a new 4bbl and complete tuneup. I have left the secondaries alone for now, that's fine-tuning for me.
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