Ok I have a 86 xj with 35s my trail rig and I want to get a little more out of the 4.0. I heard you can put the 4.2 heads and cam in for a little extra only reason I am think about it is cause motor it do for a rebuild this winter. Anyone have any other ideas and info if the head swap would work that would help or what should I do not looking for gobs of power.

 

I dunno about the 4.2 heads... but what people are doing is taking a 4.2 crank and rods, and some .30 over pistons and making a 4.6 stroker. (little time at the machine shop required obviously, along with a few other things like upgraded injectors and big bore throttle body).

 

Thats what I would do if I wanted to stay with that engine.

I run 35s on my sport and the 4.0 isnt doing it for me, so Im gonna ladder the frame and custom reinforce it. Chevy 350.

 

What gears are you running? With 35s you really should have 4.10s or higher, or else it's going to feel anemic.

 

maybe that is what there talking about

i dont want to do that this time i swap the stock 4 banger out of my gmc sonoma for a built 350 to turn my 44s over

i dont know what gear are in it i have to go look now i just picked it up and the guy used it for plowing snow

thank for the help