4.2 to 4.0 head swap head bolts? - JeepForum.com
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 Wrangler Forums > YJ Wrangler Technical Forum > 4.2 to 4.0 head swap head bolts?

G2 Disc Brake Conversion Kit for Jeep Wrangler YJ TJ LJ ChRough Country Jeep Suspension Deals at Rockridge 4WD!Rockridge 4WD IS Taking Zone Offroad Suspension Lift Kits

Unread 09-07-2011, 03:04 PM   #1
Registered User
1990 YJ Wrangler 
Join Date: Nov 2010
Location: North Salt Lake, Utah
Posts: 33
4.2 to 4.0 head swap head bolts?

I have read a bunch of posts about there being different lengths of head bolt? I have a 1990 wrangler with the 4.2 and have a head (casting 7120) all ready to go. I know I have the 1/2 inch head bolts due to its the last year the wrangler had the 4.2, but I have read that a bunch of people have had issues with the 4.0 head bolts bottoming out, and then some saying they didn't have an issue. I am just curious on what everyone out there has used? or if my best bet is going to be to tear into it and once I get to that point put the project on hold and wait for the right bolts to ship. Local dealership wants $27ea for the studded ones, and $5ea for the regular ones. I can find a whole set for about $45 but they say either 4.0 or 4.2, any suggestions?

DoozerPeej is offline   Reply With Quote
Unread 09-07-2011, 03:38 PM   #2
Registered User
1990 YJ Wrangler 
Join Date: Sep 2006
Location: Leeds AL, Alabama
Posts: 1,715
I beleive I used all of my 4.2 head bolts.
90 YJ, 4.2 with 2150 carb 4.0 Head and headers, Nutter with TFI and MSD. 1" BL, 2.5" spring lift, 33", Goodrich KM Mud Tires. Dana 30 w Aussie, Ford 8.8 w LS. 9000lb HF Winch.
Alabamaranger is offline   Reply With Quote
Thread Tools

Suggested Threads

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.