AMC Eagle Den Forum

The Mighty 258 => The Engine => Topic started by: AMCLOVER258 on July 23, 2015, 07:52:44 PM

Title: 7120
Post by: AMCLOVER258 on July 23, 2015, 07:52:44 PM
Hey guys I'm picking up a 7120 head on Sunday for 50.00 paired with the factory headers, what is the best method for plugging the water jackets & is the 7120 the one to go with or is 0330 preferred? i think for 50.00 i can't really beat it...  Also I've heard there is some mods needed to fit the 4.0 exhaust with the 4.2 intake(i'm keeping carb for simplicity) what modifications are needed to pair the two?
Title: Re: 7120
Post by: Amc1320 on July 23, 2015, 10:26:53 PM
I put the 258 intake on a 4.0 head, all I had to do was grind off the "ears" a little bit as the dowls are in a little bit different spot, it was pretty easy

Title: Re: 7120
Post by: AMCLOVER258 on July 23, 2015, 10:45:37 PM
OK, so its one of those stick'em together and cut what is in the way kinda things? hahah
Title: Re: 7120
Post by: AMCLOVER258 on July 23, 2015, 10:46:29 PM
And how is the drivability with the 4.2 intake and head on the motor compared to stock?
Title: Re: 7120
Post by: rmick on July 23, 2015, 10:51:09 PM
To plug the holes I used water soluble packing peanuts in the holes and then filled with JB weld. Been holding for 4 years. This method came from several jeep sights.
Title: Re: 7120
Post by: AMCLOVER258 on July 23, 2015, 11:49:05 PM
Good to hear. I've read of numerous different ways I was just curious as to what had worked for any folk here. 4 years is a solid measurement  :occasion14: