Will a holley 6425 drown my 258? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep CJ Forum > Will a holley 6425 drown my 258?

JK Front 3 Link Prototype - Clayton Off RoadDon't forget the Jeep Forum discount, 10% off!Ruffstuff Axle Simple Swap Kit!

Reply
Unread 02-19-2013, 02:07 PM   #1
blaylock6502
Registered User
 
Join Date: Feb 2011
Location: Wadesville, Indiana
Posts: 110
Will a holley 6425 drown my 258?

I was thinking about ordering a new intake from clifford performance but it says its made for no less than 350 cfm. Right now I just have the 1bbl and was going to put a cam in new intake and carb. I'm a gm factory trained tech but at the age of 29 working on carbs may as well be working on alien spacecraft. I have a holley 6425 which from what I've seen is a 650 cfm 2 barrel.? Is this too much or is there a chance or a way to make it work?

blaylock6502 is offline   Reply With Quote Quick reply to this message
Unread 02-19-2013, 02:48 PM   #2
19jeep85
Registered User
1985 CJ7 
 
Join Date: Feb 2010
Location: , Montana
Posts: 185
Way too much carb by about 2 times the CFM. Get a 2100/2150 motorcraft or even a Weber. Also IMO stay away from the Clifford intake as its for high reving motors.
__________________
The heart of the wise inclines to the right, but the heart of the fool to the left .
19jeep85 is offline   Reply With Quote Quick reply to this message
Unread 02-19-2013, 02:54 PM   #3
timgr
Registered User
1975 CJ6 
 
Join Date: Dec 2012
Location: Medford, MA
Posts: 463
A carburetor uses vacuum both as a signal and as power to meter the gas. If you have too big a venturi, the vacuum will be low and fuel metering will be poor. You can still make the big carburetor work by setting it up rich, so that the engine always has enough fuel.

I'd skip the 4V entirely and go with the aluminum Jeep 2V manifold. Either the Motorcraft 2100 2V or the Weber 2V work well with this manifold. The Weber comes in a 32/36 progressive type, that is like half a 4V in function. It also comes in a 38/38 non-progressive model, for higher performance and less economy. A throttle body from a 4.3L Chevy V6 also works well, but you'll need the rest the stuff to support TBI.
__________________
1) '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS, hubcaps. 2) '82 J20 360/T18/NP208/3.73, KOs, 7600 GVWR 3) '75 CJ-6, 304/T15, PS, BFG KM2s, soft top 4) '95 VW Golf Sport 2000cc 2D
timgr is offline   Reply With Quote Quick reply to this message
Unread 02-19-2013, 02:55 PM   #4
blaylock6502
Registered User
 
Join Date: Feb 2011
Location: Wadesville, Indiana
Posts: 110
Awesome. Thanks 19jeep85. Any recomendations for intakes. The reason I want to change it is its thicker I'm guessing to run with factory exhaust manifold and possibly for a different year because power steering attachment doesn't work. Overall what I'm going for is a reliable engine with a little bit of a lope at idle any input is appreciated
blaylock6502 is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools






Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.