304, 360, or 401

sling5ben · #1 (**permalink**) 01-07-2008, 12:02 PM

I am rebuilding my 82 CJ5 and am planing to replace the 258 I6 with a 304,360, or a 401 V8. I am wondering witch of the three engines is more reliable or beter choice.

Bounty__Hunter · #2 (**permalink**) 01-07-2008, 01:45 PM

Welcome to the Z.

Can't speak for reliability, but I've seen many 401's make gobs of power. Being in a small CJ5 I'd go with whatever was affordable and available.

Junkpile · #3 (**permalink**) 01-07-2008, 02:00 PM

It depends on what you want. If you just want the V8 sound and moderate power, then the 304 makes a nice option because it can still be really economical if set up right. The 360 is a better choice if you want a little more power without really going crazy. They are cheap to obtain because they are so common. If you really want to go all out with an AMC V8 then the 390/401 is the hot ticket. Forged crank, forged connecting rods, more webbing in the block... It will make more power than the other two, and still be more reliable.

I tend to recommend a 360 for most people. They are plenty durable if you keep it under 6000rpm, and you can make really good power with them.

dave123 · #4 (**permalink**) 01-21-2008, 09:58 AM

I would consider the 3 identical when it comes to reliability. I have had several AMC v8's and most of the parts are interchangeable.

Basically, you get bigger, you pay more for gas, but get better power. The upfront cost will be a little more on the bigger engine as well.

mrmopar02 · #5 (**permalink**) 01-21-2008, 07:21 PM

I'd say go with either the 360 or the 401. The 401 would give you some serious bragging rights.

carriss · #6 (**permalink**) 01-21-2008, 08:00 PM

What's your plans for the old 258?

big_o_tom · #7 (**permalink**) 03-31-2008, 11:41 AM

I've had a CJ-7 with the 258 and put a 360 in it, WOW. With a 2 barrell carb it would go! The CJ-7 I have now had a strong 304 in it. I put a '74 401 in it. Had the block bored .30 over, new piston's, bearings, 2 new valves, both heads cleaned up. Edelbrock performer carb, intake, cam and lifter's. Header's, Jacob's Ultra coil and wires. 4-core radiator, duel oil filters and an oil cooler. The motor and extra's cost about 2 grand, and it is absolutely unreal how much power and torque it has. I've always wanted to get it dyno-ed but don't where to get that done. For more power the only other motor to look at would be a 401 out of a Javelin, maybe. I have scout axles with 3.07 gearing and a t-18 tranny, at 55 mph it will get 14.5 mpg.

BaconYJ · #8 (**permalink**) 03-31-2008, 12:26 PM

Remember with the more power you are pushing, the less go-go peddle happy you can be (Lol, like that happens) or you start breaking other parts fairly easly.

Bacon

David · #9 (**permalink**) 03-31-2008, 02:39 PM

Bacon brings up a good point. With a 304, you might get by with the stock drive train parts. The more power you get, the more you're looking at upgrading or replacing in order to keep the tranny from dying, U-joints from breaking, etc.

I have a 350 in a CJ-5. That makes plenty of power for my purposes. I don't know the HP--it's pretty old, but has some upgrades. I run a T-18, so I don't have worries about my tranny giving out, but I've broken one U-joint on my Dana 30 front axle. I've also stripped the splines on one D44 shaft. I'm pretty judicious in my use of power, however, and I run mud terrain tires but not ones with super aggressive lugs. I have a feeling that if I ran stickier tires, I'd do more damage and would have to upgrade more drivetrain parts.

jeepin916 · #10 (**permalink**) 05-28-2008, 01:46 PM

there all good engines but i would go with a 360, they seem to be more available than the others...

woodie92 · #11 (**permalink**) 07-16-2008, 04:23 PM

Quote:

Originally Posted by sling5ben

I am rebuilding my 82 CJ5 and am planing to replace the 258 I6 with a 304,360, or a 401 V8. I am wondering witch of the three engines is more reliable or beter choice.

i bought a replacement 360 for mine( after blowing the head gasket in my old one) for 100 bucks! they r plentiful and cheap to buy, all of them r expensive to buy parts for! my 360 is a torque god however i love it.... the gas milage is crappy. once u get it on the trail u forget about that and the grinnining doesn't stop.
i plan on rebuilding my blown 360 with a wild cam and over bore, you had better do research on frame problems( needs some support, especially with big tires), i would add an aluminum radiator into the build or you will have overheating problems like i did. it stinks to be running 65 up the highway and see water blowing out the exhaust without warning!