You can help me to choose a Jeep!

[Wildthing]

Hi everybody,

I'm now searching for buying a Jeep but I would like to know a couple of things before. First of all, technically, what's the difference between the CJ-5 and the CJ-7? And between CJs and YJs?
Talking about the engine now, anybody have something to tell about the AMC 304 V8? Is it good for off-road?
Finaly, the stock 3-speed transmission of the late 70's CJs is it okay for off-road and road use? I mean is it okay to go around 60-65 mph on highway and is it able to go slow enought on very hardcore trail?

Well, I'm asking maybe for a lot of infos at a time but I'm sure that many of you can learn me a lot of things! I'm a new "jeeper"... but not really a new "off-roader"!

Thanks for answering!

 

[jay79cj7]

The CJ-7 is basically a stretched CJ-5. They lengthened the body a little bit (about 10") to accommodate an automatic transmission, but there are manual CJ-7's as well. Most of the parts are interchangeable between the two CJs. If you are tall, I would suggest going for a CJ-7 because it gives you more leg room. Also, if you want a hard top, it will be easier to find one for a 7.

"Newer" YJ's have fuel injection, while the first few years had the same carburated 258 that the CJ's had. The 4 cyl went FI a little bit sooner in the YJ I think, but I don't know exact years. If you go YJ, I would suggest that you go fuel injected.

Speed is going to be a function of transmission, axle gearing, and tire size. These three variables interact. There are different axle gear ratios out there from the factory, and then alot of people take them lower too for off-road purposes or to match bigger tires. Unless you go for an low ratio set of axles with smaller tires, you shouldn't have a problem doing highway speeds. Big tires with higher gearing could give you bad off-road and on-road results.

If you are talking about the 3 speed TH400 (Turbo 400) auto transmission in the 76-79 CJ-7's, I like mine, but haven't really trail tested it. I hear its good off-road, and its supposed to be one of the tougher automatic transmissions out there. They put it in the 70's full size jeeps behind the bigger V8's, so it can take a load bigger than most CJs will give it.

I don't have experience with the 304. I have heard its a good engine, but from what I have gathered, the majority of experience around here is with the I6. Good luck searching.

 

[Junkpile]

If you are talking about the T-150 3 speed, it's okay. I like mine for mud and sand because I can hold it in gear a little longer and usually I don't have to shift at all which allows me to continue forward momentum throughout a pit. Slow speed wheeling isn't a strong point when you have a 2.99:1 first gear in the T-150 and a 2.03:1 low range in the dana 20 transfer case......actually it sucks. Around town driving with the three speed isn't too bad with a V8.

I love AMC V8s. The 304 is overlooked way too often. Swap on a shaved set of the big valve/ dog-leg exhaust port heads from a 360 or 401 and get a healthy cam designed to take advantage of the larger lifter found in the AMC V8, and a 304 quickly becomes a flat-out screamer.

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[Wildthing]

Thanks guys for answering quite fast! I'll keep all of this in mind when I will look at some Jeep before buying.

 

[redrooster]

The 304 is an excellent reliable motor and will last quite a while. The only bad part is that they are expensive to rebuild if you do it right. It is less expensive to swap and adapt a chevy motor than to build the AMC V8.
My 78 CJ7 originally had a 304 with a T-150 3 speed and a dana 20 on narrow track axles. It is perfect for tooling around town but suffered on the trails. Now it has an AMC 360, th400 auto, Dana 20 and chevy ful width one tons stiing on 39.5" boggers. That's just the way it has progressed since I bought the Jeep six years ago. It has evolved along with my need to try new obstacles.
If you want to go old school like some of us then I would suggest finding an early to mid 80's CJ with a 6 cyl, T-176 four speed, Dana 300 sitting on wide track axles.
If you want a bit newer then go with a TJ withthe 4.0. My favorite thing about the TJ is that it has a much better frame than the CJ's. Otherwise I prefer the components on the CJ.
Just my opinion though. It all really depends on the ratio of street time to trail time.

 

[jay79cj7]

Redrooster,

How hard was that to adapt the 20 to the TH400? Did you have to change the output shaft of the transmission?

Thanks,
Jay