[Mol]

I just got a text message from one of my friends. He is swapping a small block for his 4.0 HO, and he wants to sell his 4.0 and ax-15. I'm still waiting to hear what he wants to sell everything for, which may be a determining factor.

What are your opinions on a head swap with howell kit vs. head swap with weber vs. swapping for the full motor.

He has had issues with his yj, and he seems to think that it is either a bad sensor in the tranny or a sensor in the wiring harness? If its a bad tranny, that's fine, mine is great. He is not a close friend, so I really don't know what his exact issues have been, just that it intermittently bogs down real bad and is almost completely devoid of power.

Swap for the motor or continue to build my 258?

[warhog-06]

If it were mine I would do the head swap w/ weber carb (which is actually what I am getting ready to do). Sounds like there is some trouble somewhere, by just using head you eliminate all electronic issues, etc. Changing the head, adding weber carb, and removing emissions (if possible), should gain you 40 - 50hp. Just spend a few hundred bucks and have the head decked (if needed), valves ground, etc., before installing. Nothing worse than going through the trouble to change head and then find out it is warped or the valves leak.

[Mol]

Yeah I have already bypassed emissions. Thanks for the input, you have affirmed my thoughts exactly with the potential troubles with his setup. What should I offer him for the head? I see people asking between $120-$200...but we all now what people ask and what they net are two entirely different things

[warhog-06]

Hard to say. Some people would want to charge you more to take the head off (more work for them). Most wouldn't want to remove because they want to sell the engine as a whole. However, try getting it cheap (since you know there are issues), and you have to have it machined. Maybe he will bite (pull it your self?).

[Mol]

yeah pretty good chance I can get it for a good deal...he has a mutual friend do his work, and I am the only other jeeper he knows. He wouldnt have anyone to sell it to otherwise. I'll give it a shot at $50 and see what he says

[warhog-06]

Now your talking. If you get it for $50, I'll buy it from you for $60. LOL

[Mol]

Think I'm safe using the exhaust manifold and intake manifold from his motor? Or do I look at buying new?

[warhog-06]

I would go ahead with his. There isn't much to go wrong with them, just clean and check everything over good. Definitly new gaskets. Good luck.

[green89yj]

So you have to get a new 4.2 head gasket and JB weld in the extra water jackets. Which pushrods and stuff do you use?

[lclark2074]

to keep the carb you will need the intake from the 4.2 and the ext from the 4.0

[ThisGuyUKnow]

If you are getting the whole drive train and want to keep the 258with the 4.0 head why not use all the fuel injection components? That way you get the benefits of MPFI over a carb.....

You will also have the parts between the 2 motors to make a 4.6 stroker which is basically a 4.0 with the rods and crank (if you want it to run off 87 octane you need to have the head worked on to change the compression a bit) it could be run with the stock 4.0 computer or a carb since the 4.2 intake will bolt to a 4.0.

[wendell]

On my 4.2, I swapped on a 4.0 HO head, comp cam, rollor rockers, offy intake, holley 470 TA 4 barrel carb, header, DUI and MSD. It romps and there's no sensors or computer to worry about. EFI is great, but it's not the only solution for the 258. The holley TA series 4 barrels are made for off road and will take some extreme angles and there dependable as well as easy to work on. I'm very happy with the power and simplicity of a carbed 258. It makes more power than a 4.0 at a little lower rpm to boot.