Jeep Strokers

So I usually build V8s but this is my first Jeep engine build. I am looking to do a 4.6 stroker with a kit from Cleggs although I may source the pistons from Russ here. My biggest question is this, I want to do this right and get the most bang for my buck while maintaining reliability for a daily driver. My Jeep is a 1995 Grand Cherokee with the 4.0 and with the added weight of armor and trail gear/ wheels and tires and such it's gotten super sluggish. Add to that it's almost at the 300,000-mile mark and I'm sure it's getting tired. I know gears will help as well but I figure it wouldn't hurt to do an engine as well. I have looked at the stage 1 Cleggs kit as I want to retain the stock computer and all to make it easy however IF I could go for the stage 2 kit and it would still work this may be a better option for the added power. I plan on the upgraded injectors, rings and bearings, balancing and such. Current engine is factory except for the Banks header I installed when the factory one cracked. I know being on a computer that my cam and all will be limited so anything I can do to give me some extra umph while maintaining the factory computer without issues would be great. The block I have for use is a 99 Cherokee block I got for basically free. I will source a head or use my current one just send everything to machine shop of course.

One of the challenges with the older computers is that they are ODBI which limits the tuning within the computer itself. Later JTEC/JTEC+/NGC3 ODBII PCMs for the 4.0L are supported with HPTuners. I don't know a ton about the ZJ, but I think the later years with the 4.0 do have JTEC PCMs and may be compatible with your instrument cluster. That's worth looking into. HP Tuners allows some fine tuning of the spark advance and injector pulsewidths to support the the new motor. In general the computer will adjust the fuel in closed loop to maintain a 14.7:1 or lambda of 1 when the injectors are close enough with the new load. However on open loop, the programming may not have the optimal injector pulse calculations for your build. 24lb/hr injectors are generally the go to for for 4.6L stroker, but they may not be perfect for yours on the stock PCM.

You may want to have an additional bung welded into the header in order to run a wideband O2 sensor and keep an eye on your air fuel ratio in wide open throttle. You generally want to target a peak of approximately 12.6:1 or 0.85 lambda with the 4.0L on wide open throttle when power enrichment kicks in and most of all make sure you don't go lean.

I have a '95 ZJ with a 4.6 stroker; '96 block, Cleggs sourced internals, '04 head. Your goals sound very much like what I accomplished with my build. Here is a link to the engine build: https://www.jeepforum.com/threads/high- ... d.4467732/

To put it into context with the rest of the vehicle, here is my overall build thread: https://www.jeepforum.com/threads/time- ... 4/#replies

Hopefully you can glean some ideas there. All I can say is I'm having challenges with other aspects of the vehicle, but am loving the engine I built.

mpgMike wrote: ↑December 30th, 2025, 7:14 pm I have a '95 ZJ with a 4.6 stroker; '96 block, Cleggs sourced internals, '04 head. Your goals sound very much like what I accomplished with my build. Here is a link to the engine build: https://www.jeepforum.com/threads/high- ... d.4467732/

To put it into context with the rest of the vehicle, here is my overall build thread: https://www.jeepforum.com/threads/time- ... 4/#replies

Hopefully you can glean some ideas there. All I can say is I'm having challenges with other aspects of the vehicle, but am loving the engine I built.

Very nice build! While I don't plan on messing with the stock ECU unless absolutely necessary, at least if I have to now, I will have a good direction to go in with your info!