Hi
Tim,
Changing jets in a Holley is pretty easy, but sometimes messy. If
you have a vacuum secondary carb, most likely you only have primary jets.
Start out by disconnecting the fuel supply line from the carb. Next get
a small cup that will fit below one of the bolts that holds the float bowl
in place. Then remove one of the lower bolts and let the fuel drain into
the cup. Once the bowl is empty you can remove the three remaining
bolts. After that, remove the float bowl. If it's been on there a
while and has standard gaskets it will take some effort to remove the
bowl. After the bowl is off, you'll see the jets screwed in at the bottom
of the metering block. Use a large fat tipped common screwdriver to
unscrew the two jets. The jets are stamped on the side with what size they
are. Holley recommends going up/down two jet sizes at a time because you won't
see much of a difference from one jet size. After you get your new jets,
install them and rest of the carb parts, start the engine, check for
leaks and you should be good to go. You may want to buy a few different
size jets too to give you some options along with a set of "non-stick" gaskets
so it will be easier to take apart in the future.
If
you're still not sure about doing this yourself, I highly recommend you pick up
a book about Holley carbs. If nothing else, it's good
reading.
Herb Lumpp
http://users.adelphia.net/~hlump/index.htm
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of Roemer, Timothy
Sent: Friday, March 25, 2005 9:33 AM
To: [email protected]
Subject: [Chevelle-list] Holley 4150 rejetting
Importance: HighI just bought a 69 Chevelle (L4-400 hp) from someone who lives on the west coast. The Holley street avenger carburetor (770 CFM) manual recommends a decrease in the primary and secondary jet size of one jet per every 2000 feet above sea level. The plugs are a dark black color so I am running a very rich mixture. I live at about 7000 feet. Does anyone know what the right jet size should be for this setup? Are the jets easy to change or should I find someone who is an expert in carburetors?? Any help would be appreciated.
tim
