Best Bang For Buck Engine Configuration.

Howdy all, I've got a 75 CJ5 that I'd like to get going this winter, I've got a few choices for engine and just curious if there's a better choice or even a Frankenstein configuration that'll be worthwhile. I currently have the complete original 232 (non power steering) engine that smoked a lil, a "running" YJ 258 that I picked up cheap, and a 4.0L long block from an early 90's, I believe, Grand Cherokee. My initial thought is just slam the 258 in it and go (after I swap the carb and add HEI) but I figured since all the engines are out and on stands i'd ask the question. I am fairly mechanically competent and I have owned many jeeps over the years including a YJ with the 258, a Jeepster, a couple TJ's and many XJ's and a few Grand Cherokee's of various vintages lol.
Thank you for your time!

 

My opinion is that the 232 is the least desirable.
Go with the 258 if you prefer carbureted.
Go with the 4.0 if you want fuel injection.

 

I have always thought of the 258 as the best engine ever put into a AMC Jeep.

So, the 258 would be my choice. It has a longer stroke than the 232 producing more torque at lower RPM.

It is a simple, nearly bullet proof engine, it will fit right in as a replacement for the original 232, and you don't have to track down the parts to complete the "long block" nor rig up the electronics needed to run the 4.0L.

 

Could you stab the 258 rotating assembly into the 4.0 block and build a stroker?

 

It has been done, but the 258 already is a "Stroker", and with some improvements to aspiration it can deliver impressive results.

From what I read in the original post, and the title of the thread, he is interested in the best bang for the buck. He has a running 258, but only a long block 4.0L engine. The best bang for the buck is to use the 258 rather than doing a complete rebuild of the 4.0L engine.

I did find an interesting article on building such an engine if you want to read about it.

https://www.rockcrawler.com/techreports/stroker40/page2.asp

 

Keep it simple. Go 258 but I would ditch the YJ carb and put the 232 carb on the 258 and see how it runs on good engine stand that won't tip over.

 

X2

 

That is what I have in my YJ. I bored 60 over and shaved the head and block installed a mild Rv cam with mc2100

 

The 258 is awesome but once a V8 Jeep goes past you'll be kicking yourself for not going straight to the V8. My 258 is out and my 360 is going in...

 

Anybody remember the old juice commercial where the guy slaps his head and says "wow, I coulda had a V8!"

Wish I had never sold my V8 '5
But the 350 Wagon doesn't suck

 

I have a 360 in my '74. It has intake, 4bbl, and headers and scoots the Jeep along quite nicely. It's a lot of fun but it has a different vibe (to borrow a term from my kids) than a good old inline six CJ. I doubt that I would remove a good running 258 to install a 360. Well... maybe not.

 

Those engines are only 11% different in displacement so your not going to gain much swapping stock stuff onto the other motors. best bang for the buck will be with whichever motor is most ready to go... slap the 232 in then you can build the 258 with 4.0 Frankenstein motor.

Camshafts make a huge difference in how a vehicle drives so that would be something to look into for the fuel injected long term motor that you build and swap in when ready.

 

Add fuel injection and a good ignition system and the 258 is perfect. Stalled on too many hills and it is not a good position to be in. Mexico had a 282 c.i. version of this engine.

 

To add my 2 cents. I'm running a 232 bored .040 over, Comp cams High Energy 260 cam, Later model 258 intake and exhaust manifold fitted with a weber 38. The pistons for a 258 that had a taller compression height and gave me a .002 deck height. Calculates out to 9:1 compression. I have to say this engine far exceeded my expectations, it holds it's own pulling hills on the highway and has more than enough power off road. All I'm saying is, don't rule out using the 232 or use the 232 crank with a 4 liter and make a mini stroker.

 

The 232 in the 4.0 makes a stroker? What displacement would that be?

 

Comes out to be 4.2 liters. This is a good site for stroker combinations. https://www.jeepstrokers.com/forum/viewtopic.php?t=3083.

 

You get a few more cubic inches if you put the 258 crank in the 4.0 block. I'm not sure, but I think that combo requires that you use the head off the 4.0. That may or may not be a little issue if you want to run an earlier carb and manifold.

I choose the 258. Mine runs great all stock with the exception of an Offenhauser manifold and Motorcraft 2150 combo.