Engine Swap Suggestions


Here are some comments from the CJ-3B Bulletin Board on possible engine swaps for a flatfender Jeep. They are ideas only, and do not cover all the modifications that may be necessary. They should not be considered step-by-step guides -- the only document of that nature on CJ3B.info is Bruce D. Osborn's Jeep 225 V6 Engine Conversion Manual.

Andy Stock summarized the situation: "As Hurricane engines are becoming harder to find, some Jeep owners need other engines that will bolt in. Here are a few:

151 Iron Duke

Jorge Hedges commented: "There's a GM 151 CID that fits pretty good, and sort of matches with the stuff under the hood, plus there are a lot of parts out there for it."

HWooldridge said: "The 151 was the Iron Duke, which AMC installed in the 80's (I had one). It was basically the 230 straight six less 2 cylinders. It was peppy with 3:73 gears but not a whole lot better than a fresh Hurricane. It also ran hot and would not go much over 70mph (that was fast enough). However, the straight sixes in the CJ5 and CJ7 were great engines for the job. If you can shoehorn in a 258, you'd have a real buzz bomb."

Bruce W offered: "The 151 will accept the same adapter that would be used to install a Chevy V8. These adapters are fairly common, so maybe a used one could be found, or a new one may not be terribly expensive."

HWooldridge: "The 151 began to be installed by AMC Jeeps in 1980 and I think it stayed in the line as the basic engine until Chrysler bought AMC a few years later. I bought one of the first ones in a brand new 1980 CJ5. It was a great little Jeep but the transmission was a 5 speed car model and the clutch was a hydraulic master/slave unit made in England, which was a real piece of junk. However, the engine was great so a later year model might be better or maybe I just had a lemon. At any rate, this engine and transmission should be pretty easy to stick in a 3B since it fit in a CJ5."

Frank Gough posted: "The 151 Chevy prepped long block is still available new and painted black from Mercruiser or painted silver from OMC. Both will fit the Advance Adapter for Chevy engines to Borg-Warner transmissions. If you use the complete engine setup from Mercruiser, it's available as 100, 120,130, or 140 hp."

Chevy 153

Randy Buchanan: "There are a couple of engines that have been used in flat fenders for quite a few years, so installing one is not a horrendous task. The engines are the 4 cyl 153ci Chevy and the 181ci Mercruiser. I used the latter in my CJ-5 (JP Mag Sept 2000) and it has worked out real well.

"The 153 was the base engine in Chevy II's in '63-69. It is from the GM 6 cyl. family 153, 181, 194, 230, 250, 292. It is not the Iron Duke!! The basic 153 has about 90 hp; this is not a whole lot more than an F-head. However the F-head has one major flaw; it cannot rev above 3200RPM and survive for any length of time. Most end up with thrown rods because some unknowing soul tried to keep up with freeway traffic. They weren't designed to be driven above 50 mph, and even with an overdrive they don't have the power for that kind of use. The Chev is quite happy buzzing along at 3000 all day long. With 5.38 gears and a Warn OD and 31" tires you should be running about 2400rpms at 65mph.

"There is no engine swap that I know of that doesn't take a significant amount of work! (L-heads don't count.) I would suggest that you get the engine swap book for Jeeps from Advance Adapters; it's well worth the $10 and it will answer all of your questions. The 153/181 swap requires the same basic procedure as any Chevy engine swap. You must change motor mounts, exhaust routing, clutch actuation. And yes, you must use an adapter between the bellhousing and the transmission. But did you know that lots of Jeeps have adapters there anyway? My '60 CJ-5 came with a T98 4 spd. and there was an adapter between the bellhousing and trans.

"I have seen no less than 25 flatfender Jeeps with these small Chevy engines in them, so its a very do-able project. The way you tell one of these engines from an Iron Duke is the valve cover, which is rectangular with round corners; the ID's valve cover has about 15-16 facets. 153's came in Chevy II's from '63-69 and in Postal Jeeps '67-71. All parts from the front and back of the engines -- water, alternators, bellhousings, clutches, etc. -- interchange with all Chev 6 cyl. except 292. Good Luck."

Nick Janaszak added: "I have a Chevy II 153 CID engine in my '52 M38. I didn't install it but whoever did sure did a nice job. My observations are as follows: the motor mounts are different and have been welded to a different spot on my frame. There is, of course, the adaptor between the engine and the T90. The clutch linkages are different and I see that the cross-member has been moved back a few inches. There is probably some stuff that I'm forgetting, but the whole set-up fits well and looks good.

"As far as driving goes, it's got a bit more get up and go than the old man's F-head. Parts availability around Vancouver Island is far easier for me than for him. It has an excellent power to weight ratio in the jeep and lends itself well to some four wheeling. It will also spin those 5.38's at 50mph all day long without any complaints (or overdrive).

"The one question that I often ask myself is whether I would have gone through the trouble to do all of that myself and the answer is no. I don't think that the gains are worth the money and frustration that you'd put yourself through."

A Bigger Chevy Engine?

David: "I am looking to purchase a '53 CJ-3B from a guy next week. It does not have an engine or tranny. I want it to be a good 4-wheeler, but also retain driveability. My brothers are Chevy guys so that would be preferable for a tranny and engine. What would fit, and is it possible to throw in a pair of Dana 44's (maybe even 60's)?"

Terry Wohlgenant: "You have a lot of options before you and it all depends on how you want to use the 3B and how much time, energy and money you are willing to commit. A 'good 4-wheeler' could mean different things to different people, all the way from stock to a V8-powered rock crawler with Dana 60's, lockers, 38-inch tires and exotic suspension. It sure would be nice if you knew what you wanted before you get started as it would save you money and time in the long run. If you are just missing the engine and tranny, In my opinion the least expensive thing to do would be to find a decent original F-head engine and T-90 tranny to use. Engine conversions can be expensive when you add up all the little things required on top of an expensive transmission-to-transfer case adapter.

"I don't know of a Chevy engine and tranny that will bolt in, but any of them will fit in the engine compartment with different degrees of modification. The small block V8 and 4.3L V6 are popular swaps as well as the Buick 3.8. Look real hard at the 80-inch wheelbase when you consider an engine/tranny combination. The rear driveshaft can turn out very short.

"There is no stock front Dana 44 as narrow as the original front axle in the 3B. Scouts used a 44 front and rear and are pretty close in width, I don't remember exactly maybe 3inches. Jeep Wagoneers used the 44 as well but are considerably wider. Of course if your brothers are Chevy guys the 1/2-ton pickup used a 44 up front, again pretty wide axle. Stepping up to the Dana 60's will be expensive. All of these axles will take some modification to work.

"Here is my choice: Chevy fuel injected 4.3, Dana 30 front axle (bolt in) with disk brakes, SM420 tranny, model 18 transfer case, original offset Dana 44 in rear with one piece axle shafts, locker and 11-inch brakes, Saginaw steering conversion and firewall mounted power brake master cylinder. Of course after I bought my very rough 3B with the intention of doing the above, I found it had a pretty low serial number and now I can't bring myself to do it. It will eventually go back to stock. Thanks to the 3B Page for that. Whatever you do, don't strip it down and lose interest."

David: "I will use it to 4-wheel, but probably not anything too bad. My main worry is actually the top speed. I'm not expecting anything like my Acura, but it needs to be able to cruise on the highway. I make frequent trips to Nebraska over the summer (about 600 miles round trip) so it needs to be able to do 80mph plus. I normally wouldn't be concerned about this, but I don't want to have to tow it out there. I had a CJ-7 about a year ago, and it handled good at higher speeds. I read somewhere on this site that you shouldn't drive these things over 40-45 mph. But he said he had a V8 and big tires, so maybe that is why? I don't know much about Jeeps (except for how good these things look), soooo, I need any help possible."

Terry: "I hate to dampen your enthusiasm but I REEAALLY think you should reconsider this. Asking a 3B to run at over 80 MPH is like using your Acura to 4-wheel. The CJ-7 you owned had a longer wheelbase, wider frame at the rear which allowed wider leaf spring mounting points and is heavier, making it more stable at higher speeds. Even at that the Ralph Nader influence with concerns about rollovers led to its demise and the introduction of the Wrangler. The 3B has an 80-inch wheelbase, relatively high center of gravity and is pretty boxy shaped. I'm sure you could put in a drivetrain to push it over 80 but it will be a white knuckle ride. That's going to be a fatiguing 300-mile trip even with upgrading the steering, seats and suspension. You're asking a lot of an almost 50-year-old vehicle whose intended use was very utilitarian."

David: "Thanks again Terry. I will probably keep it as original-looking to the untrained eye as possible. Of course, with any serious modifications it will have to be unoriginal. But, I guess going 80 doesn't sound like a good idea, so I suppose I'll throw that out. Not a big deal anyways. Although I liked the idea of the four wheeling Acura...I'm going to be looking at a truck tomorrow that can tow a good amount of weight. So I will probably just tow it places."

Mike MacDonald asked for advice on installing a Chevy 283 small block into his 3B. "I picked up a 54 CJ-3B about 3 years ago. I am now looking to make improvements to it and the top priority is the engine. It is currently running a 2000cc Pinto four banger. Needless to say, it needs some help. I think that I want to do an engine conversion. I have access to a free 283 V-8 Chevy engine from a '64 El Camino. I am concerned about the increase in power and torque, so I plan on keeping it on the tame side. "I am pretty sure that it will fit in the engine compartment, but my real concern is with the rest of the running gear. I know that the old GM SM-420 transmissions are very desirable. Will the 283 bolt right up to it? Does anyone have any advice? Should I go with the 283 and SM-420 transmission and get an adapter for the transfer case or leave the original T-90 in there and get an adapter to make it work with the 283? Or should I go in a different direction all together?"

Coby replied: "I have '58 CJ3B that I purchased with a '65 283 already in it. It is fun to drive with all of that horsepower but I do have a few inherent problems with it. First, the spark plugs are difficult to get to on the driver's side because of the off set of the drive train. Second, it is difficult to keep cool; there is very little room for a conventional or electric fan. Lastly, I have noticed that the leaf spring hanger frame mounts have been welded as if they needed strengthening. In my opinion, the best engine for this would be a 4.3L V6, they are cheap and are just a small block Chevy with two cylinders cut off so that everything will bolt up."

Mick added: "I have a 1959 Willys with a '56 or '57 265 Chevy. It's a very tight fit, the frame has had the front shackles re-welded a few times and the clutch linkage had to be modified. As a result, it is a little harder to push in the clutch. There was no room for the oil filter so it was just capped off; I put a remote unit on it."It has no problem with power; I've twisted off drive-lines and torn the spider gears out but never had any problem with the stock transmission or transfer case. I personally feel that the weakest link is the frame; it isn't designed for the extra weight of the engine. When this engine goes, I will find a modest V6 to drop in."

JC provided some further information: "First, to install the V8, you will have to remove the inner radiator shroud. The Chevy V8, along with the 4.3, has the distributor in the rear of the engine; therefore, notching the firewall is needed. The V8 is too much for the T-90; you will find some who say it works just fine, but not forever.

"The 3.8L Buick V6 fits nicely, the SM-420 bolts to it, you can get the adapter for the transfer case almost anywhere, and the dist is in the front. Just remember that all of the original running gear in your Jeep was designed to operate with a 70 hp 4-banger, not with a 200 hp V8. You do the math."

Ford 2.3L

Dean asked on the CJ-3B Bulletin Board for suggestions:

"Looking to get an old 3B on the trail, and I want a cheap alternative to finding and rebuilding an F-134. Don't want the extras that a V6 or V8 would offer. Looking for simplicity. Would consider an inline 6. Any procedures or adapters or 4-cylinder engines used to accomplish this mission would be greatly appreciated.

"I have been researching for about two months and been to lots of junkyards looking. I am looking for the quickest, easiest, cheapest alternative. I don't care about power, torque or any of that, just want to putt around in the old thing. I have found many I-6 232 engines at a junkyard, from DJ's, FJ's and other Jeep and International vehicles. I also looked at some 4-cyl engines, a GM Iron Duke and some other 150-cid engines. I haven't yet found an old F-134, which would be the best option. I've read a lot about the 225 V6 swap, but it looks like an expensive route."

Stan: "I have a 3A and I am running all original drivetrain except for engine. I used a 2300cc Ford motor. My local junkyard has at least ten of these motors. They came in Pintos and Mustangs. Mine is out of a '84 Mustang. Although it is only a 4-cylinder it has plenty of power mated with the original 5.38 gears, and as I have implied parts are readily available! Not many people go looking for one of these motors, and with just an adapter plate and motor mounts it fits great."

Tom's Pinto TurboTom McHugh: "You can pick up a used Novak adapter to mate a Pinto to a T90 for around $50. Advance Adapters doesn't make fourbanger adapters. See more details in my article on a Pinto Turbo in a CJ-3B."

Howard: "Anything is possible. The Ford 2.3 would probably be a good bet. But once you have your adapter plate you would need to fabricate motor-mounts. Also, you might need to consider the throw-out bearing and pilot bushing if using a spud-shaft. Radiator hose connection (left or right?) and throttle linkage could also pose a challenge. The best engine swaps are well planned-out; remember, the engine you have available may not be the best choice for an engine swap."

Other Options

Ernie: "Is it possible to put a Chevy straight six-cylinder in a CJ-3B with no modifications?"

Another Jeeper: "It's too long. A Ford Falcon/Mustang 6 is shorter, but still too long without some mods."

Alan: "I've got a 300ci Ford straight six in my high hood, and had to do some modifications on the hood and body to get it to fit. It has a T-98 four speed, with a straight-through Dana 20 transfer case and Dana 44's front and rear."

Drac: "I've thought about using a Chevette motor as an alternative. It's about the same size and power so you won't hurt other drivetrain parts. The fuel mileage would be considerably better and they don't mind the high RPM that occurs at highway speeds. I have no idea as to availability of adapters or other installation concerns though."

Alexander: "2.8 Chevy V6. The clutch disc from your Jeep; clutch plate, fork, bearing, bellhousing from Chevy. Any machine shop will make you an adapter. Think of the power you will get, and a pretty modern design engine for $500. That is the setup I am using in my '49 CJ-3A."

Ed Wilson: "Go with the F-134. It's a bolt-in engine and there's no expensive adapter. Has to be the easiest and cheapest. If you are talking about buying another motor and paying someone else to do the work, I'd guess you'll come in around 2/3 to 1/2 the price of a conversion. Parts certainly "ain't no thang" and you will be driving a real Jeep."

Joel Haslett: "I have to agree. The 134's are pretty forgiving motors. The low end power is pretty good. If you don't have enough money for a proper rebuild they can be patched up in some cases. If you check out the F-head powered CJ-5 on the On The Trail in Maine page, that motor should have been junked several times. It has survived a spun rod bearing, and a few years ago a wrist pin came loose and wore 1/8" deep grooves into the cylinder wall. Since it was junk anyway I put it together with used rings and bearings. Now, 2 Jeep Jamborees and many trail rides later it still turns 34x9.50 Super Swampers. While it smokes some, it still provides us with a lot of fun for not much money."

Thanks to all the contributors, and Tech Editor Doug Hoffman. Further suggestions and comments welcome. -- Derek Redmond

See also these articles on CJ3B.info:

Elsewhere on the web, see information on the GM 2.5-liter Iron Duke at JeepTech.

Information on drivetrain adapters: Novak Adapters and Advance Adapters.

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Last updated 16 December 2008 by Derek Redmond redmond@cj3b.info
All content not credited and previously copyright, is copyright Derek Redmond