Been thinking about doing this on my 4.2, the process looks pretty straightforward from y'alls video. But on another note, I spotted about 30 pounds of crack at 14:22 in this video, y'all don't wanna get busted by the cops for that, lots of jail time 🤪
Great video. lot of info, Thank you. I am going to do this on my 1977 CJ5. I was wondering about how much horsepower and torque do you think you gained? I know any increase in power in a 4.2 is good. just curious
good job brother, a question that would give you more strength?, leave the "intake manifold" of 258, or place the "intake manifold" of 242 (with the holes sealed where the injectors go)
Nice video! Thanks for sharing. I’m going to rebuild my 258 with a 4.0 head and carb setup until I can get the Holley sniper efi. How do you like it so far? I’m guessing mpg is probably a little better with a better flowing head
Thanks for your video. 96-99 4.0 heads are 0630 casting #? the AMC forum guys say any 4.0 head flows better than OEM 3.8 or 4.2 heads. However they allege 0630 heads are way to go.
@@autorandom6884 I’m speaking of the 96, 97, 98 0630 casting #, do not have any crack issues, allegedly flow best with 0 mod or work to ports or bowls.
Hello I'm working on doing the same head swap now. I have same head 4.0 casting. 7120 number I believe. Wich head bolts did you use ??? I see the 4.0 head bolts in valve cover area are recessed lower than the 4.2 . Did you use 4.0 head bolts ?
What did you do about the fuel injector ports? 🤔 My '87 YJ most likely needs an overhaul & I still have my '94 4.0 that I can steal the head from but since it's fuel injected, I would have to do something about the ports(it's probably something simple but I'm still curious either way).
I just got an 89 YJ with the 4.2 and am devouring all related videos and forums at this time. I see this project covered a lot what is the reasoning behind doing this swap?
![We Test 5 Jeep Cylinder Heads [How Much is Porting Worth?]](/img/1.gif)
Great video. I would like to know answers to the questions people have asked
Awesome video as always
Been thinking about doing this on my 4.2, the process looks pretty straightforward from y'alls video. But on another note, I spotted about 30 pounds of crack at 14:22 in this video, y'all don't wanna get busted by the cops for that, lots of jail time 🤪
Good eye👍 lol
Good job, wonder if the Edelbrock head would work? And an offenhauser intake?
@@Ikillintel1 It should work just the same
@@autorandom6884 you don’t need to do any mods to the Edelbrock. Head I just checked , I’ll be going that route, great video man ✌️
@@autorandom6884 it’s been a known fact that those who show 30 pounds of crack are the most hardworking 🤪👍
Great video. lot of info, Thank you. I am going to do this on my 1977 CJ5. I was wondering about how much horsepower and torque do you think you gained? I know any increase in power in a 4.2 is good. just curious
Can you post on how it turned out?
good job brother, a question that would give you more strength?, leave the "intake manifold" of 258, or place the "intake manifold" of 242 (with the holes sealed where the injectors go)
Nice video! Thanks for sharing. I’m going to rebuild my 258 with a 4.0 head and carb setup until I can get the Holley sniper efi. How do you like it so far? I’m guessing mpg is probably a little better with a better flowing head
Did you use a gasket to match the block or the head? If you use a head gasket to match the head, is it still necessary to fill those 12 water holes?
FYI if you have the 4.2 Aluminum valve cover it bolts the same
Thanks for your video. 96-99 4.0 heads are 0630 casting #? the AMC forum guys say any 4.0 head flows better than OEM 3.8 or 4.2 heads. However they allege 0630 heads are way to go.
The later model heads to the best of my knowledge were more prone to cracking hence why I went with the early/mid 90's head.
@@autorandom6884 I’m speaking of the 96, 97, 98 0630 casting #, do not have any crack issues, allegedly flow best with 0 mod or work to ports or bowls.
Hello I'm working on doing the same head swap now. I have same head 4.0 casting. 7120 number I believe. Wich head bolts did you use ??? I see the 4.0 head bolts in valve cover area are recessed lower than the 4.2 . Did you use 4.0 head bolts ?
What did you do about the fuel injector ports? 🤔 My '87 YJ most likely needs an overhaul & I still have my '94 4.0 that I can steal the head from but since it's fuel injected, I would have to do something about the ports(it's probably something simple but I'm still curious either way).
I just got an 89 YJ with the 4.2 and am devouring all related videos and forums at this time. I see this project covered a lot what is the reasoning behind doing this swap?
Without making it fuel injected? I don't understand the significance. I have an 88 with a crown 2bbl nand an HEI. It does pretty good.
Did you reuse the same rocker arms and push rods off the 4.2 head? Looking to do the same soon
Tienes algun video de como se carbura ?
How are you liking the 4.0 head 2 yrs later?
What head gasket and push rods did you use? I’m using a 1980 258 block.
In what this swap helps in performance?
Not trying to be overly critical, but IMHO the whole point of putting on the 4.0L head is to get the multi-port fuel injection.
Better flow overall. Secret to making power is in the head(s)
When you are in rural areas, far from all fuel injection is shit, nothing better than a good carburetor, it is the most reliable and simple,
How many cc on combusyion chamber?
Those back valve cover bolts are a bitch on a 4.2
Dat ass
Amc legacy
Tienes algún vídeo de como se carbura ?