I am getting about 10-11 MPG freeway with my I6 Daily Driver (82 cj-7). Obviously the 360 and 401's have more power and probably about the same gas mileage (all poor, avg btwn 8-16). Smog bridged rocker heads. Personally I like my 304. 258, 304, 343, 360, 390, 401. //--> Differences are only in displacement and whether the flywheel is internally or externally balanced. '04Ram,'99Plym.Van,"96Exploder,'79Dodge pickup, '71Jav. Noisy little suckers.
It went 6800 with ease.
Last when I swapped in a 401 into a 74 CJ-5 the motor mounts for the I6 are in the same place as the V8 so no mods required. Also the 360 is the most common. 360's were common in the FSJ's and are easier to find than 401's.
I have the 304, as do many others, because that is what came in CJ's in the late 70's/early 80's.
'68Jav, and '90 Gold Rush trailer
The 304,360,390 and 401 AMC engines are all the same block.
The AMC 360-cubic inch displacement V-8 engine was an overhead-valve design with two valves, one intake and one exhaust, per cylinder. It leaks like a mutha (front main seal and others). 401 steel crank, 360 cast. I have the 304, as do many others, because that is what came in CJ's in the late 70's/early 80's. AMC stamps the engine displacement on the sides of thier block in large numbers so its easy to tell what you getting. I am getting about 10-11 MPG freeway with my I6 Daily Driver (82 cj-7). They both behave themselves quietly under the hood while being reasonable on gas and waking up when needed when the pedal is punched. I'm not saying even a stock 304 won't scream, just don't know how much power it will make in STOCK form at high rpm, so why twist it that hard? The 304 was dropped by the end of 1981—likely due to the fact that AMC's six-cylinder was making more horsepower than it, and its emissions were no better than the 360's. The bore spacing on the engine block was 4.75 inches center-to-center. I know people love and get 200,000 miles out of the 4.0L, but alot of that is due to the electronic engine management.
I have the 304, as do many others, because that is what came in CJ's in the late 70's/early 80's. I have to drop the initial advance back about 5 degrees when they switch over each year.
I have no reservations about driving this car hundreds of miles cross-country, it has been so reliable to me. I wish I had a dollar for every one I've heard with a rod or main knock...or a wobbling harmonic balancer...or a shot water pump bearing. This new AMC engine defied categorization to a degree in that it was m… It was only pulled to go 360 for more power and more problems.I did say STOCK 304, and I don't doubt a 304 can turn the tach to 6k+. I would also look for a complete running 360 out of a FSJ so you can take everything needed; brackets, intakes, manifolds, carb, wiring harness, etc.
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If I were doing an engine swap I'd find a 360 and slap it in since it would mate directly to the TH400 I have and no need to change engine mounts, etc. The 304 and 360 share the same stroke, the 360 has a bigger bore (4.08 vs 3.75).
'); 360s are common and the only downfall I've heard on 401s is limits on how much you can bore them out and mileage. I'd do the 360 swap if I owned your CJ. The 304 and 360 are very similar except for displacement and the valve sizes. "I think 6800 is quite impessive from a STOCK long block, A cam (valve springs) intake and headers are nothing but very mild easy bolt-ons, the engine was completely STOCK otherwise. Re the AMC engines, the 401 is a great engine. Summer blends act like it's 'cut' with donkey urine. 360's were common in the FSJ's and are easier to find than 401's. It was a 272 HMV Crane. All the modern AMC engines (290, 304, 343, 360, 390, 401) should be as close to a bolt-in as is possible. Here's a link to some information I put together preparing for my 360 swap (about 2 yrs ago). Obviously the 360 and 401's have more power and probably about the same gas mileage (all poor, avg btwn 8-16). 360s are common and the only downfall I've heard on 401s is limits on how much you can bore them out and mileage. "Simply put, the small bore/same stroke/ small valves of the 304 just won't let it turn the rpm the 360 will.
Running a small-valve 304 in anything reminds me of the old saying - "dictated by poverty or a keen sense of adventure".
there is a reason why people want 401s and why people dont go crazy to find a 304/360. What is the difference between the AMC engines. The 360 was never a stock engine for any CJ series Jeep, so I suspect that it is really a 304. Aftermarket companys like Edelbrock are starting to recongnize the AMC motors more. It also explains the big price difference in cost when you travel from We have a Billion Dollar fraud outfit here called the Air Resources Board that thinks the federal fuel standards from the EPA aren't good enough. Good luck, var sidebar_width = parseInt('220px'); I can build an engine, but, I can't drain oil without a mess. The 390 and 401 are great engines but you will start getting into overheating problems with the stock Jeep radiator.
Plus bottom end torque is no contest. That is what makes a good engine in my book. I've had two 360s that both went 200 K-miles. 360(5.9L) V8 318(5.2L) V8 242(4.0L) I6 150(2.5L) I4 173(2.8L) V6 GM 151 I4 AMC 401 V8 AMC 360 V8 AMC 304 V8 AMC 258 I6 AMC 232 I6 "Dauntless" 350 V8 "Dauntless" 225 V6 "Vigilante" 327 V8 "Tornado" 230 I6 Perkins 192 I4 "Hurricane" 226 I6 "Hurricane" 134 I4 "Go Devil" 134 I4
I would also look for a complete running 360 out of a FSJ so you can take everything needed; brackets, intakes, manifolds, carb, wiring harness, etc. The 360 was never a stock engine for any CJ series Jeep, so I suspect that it is really a 304. Going from a I6 to the V8 will require changing mounts and likely a different transmission, driveshaft mods, etc. Going from a I6 to the V8 will require changing mounts and likely a different transmission, driveshaft mods, etc. The 360 heads have bigger valves. AMC stamps the engine displacement on the sides of thier block in large numbers so its easy to tell what you getting. The cylinder bore was 4.08 inches and the crankshaft stroke was 3.44 inches.