spark plugs

[tylergrant2011]

What the best plugs to run In 87 4.0 comanche

[dunnc1991]

I've always run basic champion coppers. Nothing fancy, and they always work great. Pretty popular with the 4.0

[Eagle]

First choice: NGK (conventional, not platinum)

 

Second choice: Champion Truck Plugs

 

Third choice: see above

[Incommando]

In have had very good luck with Autolite.

[tylergrant2011]

I have ap985's in it and they lasted 60000 miles

[Jeep Driver]

In have had very good luck with Autolite.

That's cause you and me are smart. :P

[COMJNUT]

Gee guys, its a over glorified tractor motor! If the motor is stock, put some cheap ones in it, make sure the gap is correct and it will run like you put those $20 per plug in it.

[cruiser54]

First choice: NGK (conventional, not platinum)

 

Second choice: Champion Truck Plugs

 

Third choice: see above

Excellent!!

[cruiser54]

Gee guys, its a over glorified tractor motor! If the motor is stock, put some cheap ones in it, make sure the gap is correct and it will run like you put those $20 per plug in it.

It is not, and never was, related to a tractor motor in any way, shape or form. 

 

http://en.wikipedia.org/wiki/AMC_straight-6_engine

[metrictonner]

I've tried everything and always come back to the OEM recommended copper core Champions.  RC9YC.

[Motorcharge]

Champion or NGK copper. 4.0 is pretty picky about spark plugs.

[cruiser54]

Champion or NGK copper. 4.0 is pretty picky about spark plugs.

Yup. Copper all the way. NGKs are the best.

[gogmorgo]

On a mostly stock motor, you won't see much benefit to running high-performance plugs, and they tend to wear out more quickly with less tolerance for re-gapping.

I'm also a fan of the NGK coppers, but have used the basic Champions with good results, too.

[Minuit]

Basic Champion plugs haven't ever given me any trouble.