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Engine Swap…To Do or Not To Do?

Chris Dunlap

New Member
Joined
Apr 8, 2025
I have a 1960 CJ-5 that I mainly use to run around my ranch and hunt out of. The original 134 locked up a few months ago. I’ve been looking around at engines and pricing them out. I can get a reman 134 from S&J Engines for about $4800 or I can get a reman 225 from them for around $2800.

The money is not the issue, although if I can get a better motor for less money that’s a no brainer. I assume that the T-90 will mate right up to the 225. Are there any other major issues or considerations in swapping to the 225?

I am putting the Jeep in my shop this winter and tearing it completely apart anyway. I plan to have the tub rhino lined inside and out after I weld up 66 years worth of extra holes drilled here and there. There is no rust at all in the body. Also on the list is, replace all of the bushings, tie rod ends, ball joints, hubs, etc. Also plan to do a rebuild kit on both the transmission and transfer case and both axles. Upgrade to 4-wheel disc brakes and build some custom bumpers. Build a completely new wiring harness, add in fuse blocks, new gauges, etc.

I know this is going to be a long and arduous process so I want to get it right the first time if possible. So if you have any comments on the engine swap I am all ears.
 
T-90 does will not mate right up to anything. It will need an adapter kit with a longer t-90j input shaft.

I would go with a tbi 4.3 out of a running vehicle.
 
T-90 does will not mate right up to anything. It will need an adapter kit with a longer t-90j input shaft.

I would go with a tbi 4.3 out of a running vehicle.
I clearly agree… but

Seems like the poster is not familiar to this kind of work. If that’s true, a running FHead would be the easiest fix. No adapters, just plug and play.

I love my 4.3 and I also have upgraded brakes and steering.. it becomes a very slippery slope with project creep.
 
Place a WTB post in the classified, here, Old Willys (https://www.oldwillysforum.com/forum/index.php), maybe the CJ 2A Page (https://www.thecj2apage.com/FORUMS/cj2a-discussion-area_forums_cat1.html), and eWillys (https://www.ewillys.com/) for a RUNNING F head. They do get swapped and running examples are out there. For your use, as posted above, I would stay with it. The caveat is finding one relatively close by.

Did you dig into the original to find out why it locked up? Any swap ends up being a slippery slope and even when you think you have the cost penciled out, you need to at least double it to be in a realistic price range. The 225 will pair with the T90 with an aftermarket adapter or the early factory cast iron adapter. As noted, that requires the long input shaft from the T90J and a near complete dismantling of the transmission. That adapter gets you to the standard GM standard transmission bellhousing mounting pattern.
 
I have a 1960 CJ-5 that I mainly use to run around my ranch and hunt out of.

Define "better."

Depending on the size of your ranch, the F-134 might be just right for that. Without a bunch of conversion costs and headaches.
 
In addition to needing to swap out the transmission input shaft (or going with the native T14 etc), the motor mounts are different between the F134 and 225. Also, would there be some fiddling with the clutch linkage? I don't believe the 225 used the same clutch tube/cross-shaft? At least the later 225 didn't, but not sure about the early 225s.
Engine swaps are a big project!
 
I don't think anyone has made this point directly so far.
Just because the 225 came in a CJ-5, it does not mean that it will bolt-in in place of the F134.
There is almost nothing about the 225 that makes it easier than any other complete engine swap.
This is why someone suggested the 4.3L Chevy V6 instead of the 225 swap.
Not significantly different in difficulty, and you can likely get the Chevy donor for much less than a rebuilt anything.

Back in the day, the Studebaker inline six was a popular swap for the F134.
Studebaker used the T-90 in its passenger cars, which made the bolt-up easier (I presume).
Inline sixes are a poor fit for the short CJ-5 engine compartment though - that's why Jeep chose the 225 V6.
Many V8s will fit too, but the V6s are easier.
The 225 has the distributor in the front, which is something of an advantage over the Chevy V6, but abundance of donors probably outweighs that.
Realize that a "complete rebuilt engine" will not come with all the external bits you will need like the manifolds, brackets, etc. etc.
A complete donor will have lots of these extra parts you'll need.
 
... The 225 will pair with the T90 with an aftermarket adapter or the early factory cast iron adapter. ...
Maybe there is a factory adapter I don't know of. The factory adapters of the T86 or T-14 to the 225 are the T-14/T-15 pattern. The T-90 pattern is smaller. I expect you could redrill the T-14 adapter to bolt up to the T-90.
 
$4800 for an f-head from S&J is insane.
Where are you located? I’d inquire about jeepstar’s offer if you’re within a reasonable distance.

And since no one else has said it yet, please don’t rhino line the tub. It’s a death sentence for these things.
 
All of the work you listed will likely be more than a winter project. I would prioritize what needs to be done and see what you can accomplish over the winter and get it back on the road for the summer. Then continue working on the list next winter.
 
As others have stated, an engine swap will have project creep. 11" drums brakes all the way around would be minimum for an engine swap along with a dual master cylinder. Then you have the transmission adaptation or swap. The stock steering is less than desirable too. A V6 ross box is a slight upgrade which is bolt in, but that gets in the way of the exhaust on the driver's side. So might as well go with manual saginaw to make room for the exhaust.

Another running F head might be the way to go if you're not comfortable doing all this work and if you were happy with how it was before.
 
The t-90 a/c used a 15/16 input shaft. The t-90 j is the same input diameter and spline as a sm465.

All the swaps need the driveline moved closer to center for the brake pedal to clear the bellhousing. 85 was the only year with a large cap hei 4.3 distributor and quadrajet. Everything after 85 has roller cam, small distributor. You just need to know the there is not one singular 4.3 cookie cutter swap. you had a family with several factories building them for several markets from fullsize vans to sporty cars.

The buick costs more now and the 4.3 didn't exist back in the 60s. The sbc v8 had just arrived and folks were swapping them in but as a manufacturer sometimes it's a matter of what you can purchase to put into a product.

If you have 0 plans on taking it on the highway than put a 4cyl back in it. Even a ford 2.3 swap can be done with a lot less work. than a v6 swap.
 
If the existing engine is working to your satisfaction, I would stay with.
Given what you are doing to the rest of the Jeep, a tear down and rebuild would be a first option.
After that a running drop in would be the second.

Other thoughts.......
I would also think about ditching the rear disc option. Rears only account for about 30% of total braking. excessive rear braking can lead to lock up and that is bad juju. The fronts are fine along with a dual master cylinder.

Do an axle inspection before you tear them down. Most don't require an overhaul (especially the front), and doing it costs time and money. Seals if leaking and fresh fluids.
 
I have a 1960 CJ-5 that I mainly use to run around my ranch and hunt out of. The original 134 locked up a few months ago. I’ve been looking around at engines and pricing them out. I can get a reman 134 from S&J Engines for about $4800 or I can get a reman 225 from them for around $2800.
If the existing engine is working to your satisfaction, I would stay with.
Given what you are doing to the rest of the Jeep, a tear down and rebuild would be a first option.
After that a running drop in would be the second.
I'm not a fan of the 134, but only because I've had it in larger Wagons. In a CJ, it works fine.

And if you do stay with the F head, think about an overdrive. A great addition that requires just an extra hole in the floor for the shifter. Makes the ol' 4 bangers so much more drive-able!

And since no one else has said it yet, please don’t rhino line the tub. It’s a death sentence for these things.
X4... Rhino Liner doesn't hold up like their marketing would like you to believe, and these old tubs flex. The slightest crack will allow water in and it will capillary to the rest of the sheet metal.
Your rustless wonder will convert to a rust bucket without you ever noticing until it's too late! Just a good coat of paint... Brush on underneath is completely acceptable ;)
 
I have done so many motor swaps in the last 45 years I’ve lost count, and as others have said, this is not a straight forward project. If you are not a fabricator/welder/decent mechanic, you are likely biting off more than you want to chew…
 
I have done so many motor swaps in the last 45 years I’ve lost count, and as others have said, this is not a straight forward project. If you are not a fabricator/welder/decent mechanic, you are likely biting off more than you want to chew…
I'm still trying to find someone to help with new motor mounts for a tranny swap after 4 years! I wish I had those welding skills!

and @colojeepguy I don't want to start a debate on RhinoLiner. It has worked well for a lot of folks for a long time. I just would not use it underneath, only in areas (like a truck bed) where I caneasily see it. And I'm with ya on the looks; remember "Zolotone"? :0
 
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