Misc. Cj7 engine options?

[Rarena]

So I want to keep my jeep a jeep. I have an 85 CJ7 runs great after a new carb, distributor, alt, pump etc. 180k on motor and was thinking about a swap. I've decided to keep it a jeep and run a 258. Obviously an improved 258. A friend gave me an old motor he rebuilt but I think it's from an older 79 or 80. I have a 5 speed. Can anyone give me some guidance? Will this work or should I just buy a replacement 81-85.

 

[Patrick]

With the “keep my jeep a jeep” mentality, you cannot go wrong with a properly rebuilt two five eight of any year. These little engines are true workhorses.

 

[Manic Mechanic]

Everything should bolt right up assuming it already running a 258. Even some of the 2.5 and 304 should work

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[Rarena]

Everything should bolt right up assuming it already running a 258. Even some of the 2.5 and 304 should work

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Thank you for the info! Saves me a little cash. It is a 258 now just want a fresh one ready to go

 

[Manic Mechanic]

There all the same except for head bolt size depending on years. I just went through all this having a 258 rebuilt

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[Project86]

Go with a 4 speed trans. 5 speed just doesn't have enough A BAD WORD in it to run at today's highway speeds in my opinion. Couple that with any kind of head wind over 5 mph and you end up running in 4th gear anyway.

 

[NP435]

Thank you for the info! Saves me a little cash. It is a 258 now just want a fresh one ready to go

Tire size and gear ratio are what you must consider if you want overdrive, for my usage overdrive is just silly with the long grades on roads in my local area. Wind alone keeps me at 50 mph if out of the west.

 

[Manic Mechanic]

I run a bw t5 with factory 3.31 gears and 31s most of the time. I've passed cars doing 80mph. Mostly 65-75 and taching around 1900-2200 rpm. Only going up steep grades so I have to leave it in 4th

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[TSB8C]

I have a 700R4 auto which has overdrive and a lockup torque converter. I do a lot of highway driving and the overdrive is great. I run 35" tires and 4.56 gears. Can do 70mph at around 2200 rpm or around 2800 rpm doing 80mph. First and second are still low enough for trails when camping/hunting. Great combo for my uses. I rarely see a steep grade (flat Houston area) except a freeway overpass. But certainly need to look at what you plan to do and where.

 

[Manic Mechanic]

But certainly need to look at what you plan to do and where.

Couldn't have said it better myself. I'm in the east coast along the application mountains. Nothing compared to what's out west but I'm more than capable around here and still got a low enough first and second when I'm wheeling

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[Patrick]

One of the things he wants to do is keep his CJ a Jeep. Nothing wrong with that.