99 Motor in a 91?

[ttruckinon]

My 4.0 is broke and I found a 4.0 out of a 99 for sale. Will it go right in my 91?

[87manche]

the brackets for the accesories are different because of the different intake. If you use your intake it should be drop in. The injectors may also have different plugs on them, easily solved if you use your old injectors, or take a dremel to the plugs in your harness.

[ttruckinon]

Thanks! Now all I have to do is buy it and swap it.

[Eagle]

You'll also need to drill and tap a hole in the back corner of the head for the temperature sender. The 99 sender in the thermostat housing sends data to the PCM and the gauges pull their data from the data bus. The '91 gauge is driven directly by the sensor in the head.

[GirsMJ86]

You'll also need to drill and tap a hole in the back corner of the head for the temperature sender. The 99 sender in the thermostat housing sends data to the PCM and the gauges pull their data from the data bus. The '91 gauge is driven directly by the sensor in the head.

 

... or just reuse the head he has on his 91. should work. i have never done it but i am told it con be done.

 

Alex