Swap a 4.0L in for your 258
Since my motor was
from a Cherokee, I decided not to run a mechanical fan. I have a massive
thermostatically controlled electric fan mounted to the front of my radiator.
It keeps the engine very cool and I have the option to go back and add
a mechanical fan if I feel it is necessary later.
The O2 sensor needs to be installed in the exhaust and the new header
connected to your existing exhaust. This cost me $30 at the local muffler
Since the Cherokee air intake would obviously not fit in my Wrangler I
chose to use a Turbo City Rock-It tube. It looks cool and sounds like
a jet engine when you get on the gas hard. I do not know if it gave any
performance difference since I do not know what it drove like with out
It is possible to use the 258 starter with the 4.0L engine. I would suggest
that you get a 4.0L starter. I kept my 258 started and I had to shim it
away form the bell housing to make it work. It works great but it did
complicate the wiring just a bit since the 4.0L starter is a different
set up than the 258.
I had to upgrade to a newer Jeep tachometer to get it to work with my
You will need a high pressure fuel pump. It is possible to use an inline
pump. I found it was more cost effective for me to buy a tank with a pump
in it from a newer Jeep. Make sure to use steel braided high-pressure
fuel line anywhere you have to use flexible line.