AMC 258 I6 performance mods -
LinkBack Thread Tools
post #1 of 3 Old 05-12-2008, 08:37 PM Thread Starter
Registered User
Join Date: May 2008
Location: Grand Rapids
Posts: 4
AMC 258 I6 performance mods

I just recently put in a brand new AMC 258 inline 6 into my 1987 YJ. It's great, but I would like to make some modifications in order to gain more hp and increase mpg. Any suggestions? The most obvious seems to get a performance carburetor or new exhaust system. Right now, it's a gas hog and often hesitates upon acceleration. Thanks.

byxbejer is offline  
Sponsored Links
post #2 of 3 Old 05-12-2008, 10:31 PM
Registered User
1993 YJ Wrangler 
Join Date: Apr 2008
Location: michigan
Posts: 134
I am in the process of doing the same install in my 89. I agree with the performance carb, personally I went with the weber. Swap the distributor for an HEI, it throws more spark. Or you could scrap the carb, do a 4.0 head conversion and go fuel injected. The 258 heads flow for crap anyway.

Good Luck,
lkg351 is offline  
post #3 of 3 Old 05-18-2008, 08:33 AM
Registered User
1987 YJ Wrangler 
Join Date: Aug 2006
Location: grafton ohio
Posts: 3,286
Yep, 4.0 head conversion and efi kit, and run synthetics in the whole drivetrain. Jaccobs omnipack helps with power and mpg as well.

1987 wrangler, 258 I-6, 5-speed.
2007 liberty sport 4X4, automatic
2009 ford ranger 4x4 FX4 OFF/ROAD, 5-speed
wendell is offline  

Quick Reply

Register Now

In order to be able to post messages on the forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.

Email Address:


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.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
"Performance chips" OBD2 plug in fpr 4.O L6, jet performance, whats the deal? jamoka3 Audio, CB & Ham Radios, GPS, & Electrical 6 10-27-2009 11:35 AM
What performance mods have you done? skenzer Street Jeep Forum 47 08-11-2007 12:48 PM
Performance? FXSTCHEWY Tires & Wheels 1 12-14-2006 10:29 AM
CB performance Highlander357 Audio, CB & Ham Radios, GPS, & Electrical 12 12-13-2005 10:13 AM
anybody rebuild there 4cyl with performance mods? GREGDOG95YJ Engines & Drivetrain 6 07-24-2002 06:26 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome