[Guest]

I have a spare 1974 258, the kid up the street just blew his motor in his 1987 Cherokee, is there any way he can use the 258, will the injection set-up work? I thought the 258 and the 4.0 was real different,i'm just trying to help him out.Any advice would be appreciated.
Thanks, Mike

 

[LooseNut]

I think he can use the 4.0 head on the 258 and make a really good engine. I do believe his 4.0 has fuel injection, which he would want to keep because his is now computer controlled. He could put the 258 in as-is, but would not be happy with the performance of the old carb engine after having the F.I.

Loose nut behind the wheel
Another right-wing conservative.....
Born and raised in Jeep-Town

 

[Guest]

Just a clarification, 4.0 wasnt available in '87. It's a 4.2.

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[dorfs]

You don't wan't to use the fuel injection from the earlier Renix systems that were used on the xj's. This system is pretty poor, and the wiring is a nightmare! I would suguest using the crank and rods from your 258, and putting them in the 4.0. This would stroke your motor to about 4.5l. The heads on the earlier 4.0's didn't flow as good as the later H.O. motors, the ones that use Mopar's fuel system, but are much better than the 258's. Then try to find the injection from a '91 to '95 4.0l to adapt, or the mpfi kit. You can also use your carb set-up with this motor.

 

[Guest]

Yes they did Stomper. The 4.0 was used in Cherokees from 87 to present. And it was also injected in 87 as well.
Steve

 

[jeepgod]

well.. here goes something hopefully for not.. take the 258.. and yes you can use the head and fi from the 4.0.. but the water jackets dont quite match.. you will have to make them match.. any machine shop can do it for a little cash.. then you will have a kickin motor.. my friend had a 4.0 head on his 258.. bought it that way..and we didnt figure it out till trying to replace the valve cover gasket.. he had always wondered why it ran hot.. never blew anything. but it did run on the hot side.. and no.. his didnt have the fi on it..

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