Engine How much can you safely bump the 4.0L and not hurt the reliability?

[bennylava]

One of the things that attracts me to the 4.0L for the old Jeep I'll be fixing up, is it's reliability. But how high can you go with HP and TQ and still have excellent reliability?

Next question!

How much hp and tq is really needed for light, and medium trails? We'll never be doing mudding or advanced trails. Would 300hp and 300tq be enough for a medium trail, while also feeling like the jeep was "fast" on the highway? Fast for a jeep anyway. Thanks!

 

[Manic Mechanic]

I have a stock built AMC 258 i6 / 4.2l only mods being EFI headers and GM HEI. It has plenty of power for trails and I've had her over 100mph. You don't need anything near 300/300 HP&tq for what you are trying to accomplish

 

[jzak]

Old man rant here, but why the heck would you buy a vehicle that was never designed for speed, and try to get 300hp out of it???? I've read these kind of posts a million times before. Its always, Do I need a LS engine swap, Do I need Dana 60's, Do I need a 6-inch lift to go off roading? Simple answer is NO! If you wanna turn a perfectly good CJ into some modded Frankenstein, it's a free country, but its gunna cost ya 25-50 grand, and a lot of broken transmissions, rear diffs and axles in the process. And in the end you'll be going up Hell's Revenge at Moab, and an unmodified CJ3 will skip past you, and you'll wish you never changed a thing.

 

[bennylava]

Oh I should have said I don't have an engine and Transmission . The old stuff died before I got it, and was yanked out, but then the project was abandoned.

So I have to get something in there, or someone on foot would pass me on the trail let alone an unmodded CJ3 lol

 

[Manic Mechanic]

I'd grab a complete 4.0/5 spd from a Wrangler drop it in. Don't worry about HP the inline 6 has plenty of power for a lite weight Jeep like that