I am building a CJ7 trailered rockcrawler Dana 60 f/r, 39.5 Boggers, 727,and D300.(100% Off Road Use) I have a 4.0 that is 95% complete I need a cam, fuel pump and oil pump it has all of the fuel injection, computer and an XJ wiring harness. I was planning to run this in the Jeep but I recently found a sweet deal on a midly built 304 with new Edelbrock 650 cfm carb etc.

Given the choice of a stock 6 cyl. fuilie or mild V8 that's carbed which would you choose to run.

Regards

MT
<IMG SRC="smilies/usa.gif" border="0">

sounds like to me since you dont drive it every day and its 100% off road use go with the V-8 later on you can put on fuel injection on that engine and you will be so happy!! The 4.0 is an excellent motor but it just wont give you the sound of a V8 and the power either. <IMG SRC="smilies/jeep1.gif" border="0">

v8, but i'd put the stock 2barrel back on it

Originally posted by The Flem:
<STRONG>v8, but i'd put the stock 2barrel back on it</STRONG>

I have the 4.0/999/300 (4:1 gears) I love it. Never needed any more on the trail I do drive mine on the street so some more HP would be nice. I say go V8 and dump that carb or you'll be sorry.

go v8, but skip the 304, get the venerable SBC 350. the 304's weight alone makes it less desirable, IMO.

Originally posted by HighHooder:
<STRONG>go v8, but skip the 304, get the venerable SBC 350. the 304's weight alone makes it less desirable, IMO.</STRONG>


Less desirable than a 350? AMC v8's weigh about 30lbs less than chevy blocks of the same era, and around only 50lbs more than a 258.

I read somewhere that the 390 amc v8 out of a 71 Javelin had the highest horsepower to weight ratio that year.

Fuellie I6 over the 306

Tough call between the 4.0 and the 360 - which are pretty plentiful

The 4.0 puts out more ponies than a stock 304, but not quite as much low-end torque. If its strictly rocks crawling, I think I'd go with the 4.0 strictly because its fuel injected. The 304 will have a little more grunt but carb's suck IMHO.

one word: cubage. the 304 has 62 cubes on a 242. better yet would be a 360. same block as a 304 but with larger pistons.
AMC v8s are torkey as hell, BTW. they're real truck engines. i've heard (never run a 350) that SBCs don't get shit for low end torque; unless you're talking about a 383.

anyway, the answer from my corner will always be to go v8, unless you're making a 242/258 hybrid.

mmmm... 281 cubes of fuel injected inline 6 madness....

go with the 4.0...

it will be cheaper in the long run

it is already FI

go with the v-8, put howell injection later, play with the carb for a little while, there are more mods to build the 304 than the 4.0 also, and amc's are easy to work on, no computer

Originally posted by redruM:
<STRONG>go with the 4.0...

it will be cheaper in the long run

it is already FI</STRONG>


I dont know about that one, you haven't seen my CJ since I put the 360 in it, but it'll run at almost any angle, just a notch under EFI. EFI can be added later too for around $1k. I'll probably be out at Gilmer over Thanksgiving break if you want to check it out, trying to find a group thats going out there one of those days.

Another vote for V8 but skip the 304 and get a 360 with quadrajet or motorcraft carb and just as easy installing a 360 as a 304.

cjboxer

Originally posted by WillyPete:
<STRONG>i've heard (never run a 350) that SBCs don't get shit for low end torque</STRONG>


i dont know exactly what you have been
<IMG SRC="smilies/smokin.gif" border="0"> , but if you think that a CSB does not have torque, you are crazy....

Originally posted by AGGIECJ-7:
<STRONG>i dont know exactly what you have been
<IMG SRC="smilies/smokin.gif" border="0"> , but if you think that a CSB does not have torque, you are crazy....</STRONG>

I agree, I've had a 3 Jeeps with 5 different engines.

The first Jeep I had was a CJ-5, 3 Speed Standard w/ a 304 -- granted, it was built by the previous owner, but it had almost no low-end torque. It would stall off-road all of the time if I let the RPM drop below 1200-1500. Essentially it had way more cam than needed. I sold the 304 and put in a rebuilt 258 (and T-176 4-speed) using some weird 2 barrel carb that had a primary and a vacuum secondary. I could put the bumper up against a wall and let the clutch out in 1st gear low range and it would just slowly chirp the tires.

The next Jeep had a 258 from an '87 Wrangler, it worked well until I burnt 2 pistons on some bad gas in Panama. When I got the Jeep back to the states, we put in a stock SBC. That engine would idle so slow going over rocks that you could literally hear each individual cylender fire. I had 3 problems with the carb on this however: 1. When it got hot outside (I live in Az, that's like 6 months out of the year) the gas would boil in the float bowl -- adding a plate helped prevent this vapor lock, a little. 2. When vacationing in Colorado, at high altitudes, it suffered a significant loss in power -- creating a small vacuum leak helped. 3. On long, steep hills, the float bowl would run out of gas -- nothing really helped this, although we did adjust the float to keep as much gas in the bowl as possible.

My current Jeep I bought came with a 350TBI already installed, I've sat talking on hills steep enough to drain most carbs' float bowls and that fuel injection just keeps it running. In Colorado, I can't even tell that I'm at 13,000 feet -- it just keeps on running just like it does at 1,000ft. The only thing I carry is a spare electric fuel pump, just in case I need it.

- Mike

the 304 would offer minimal power gain and not do as well in rough crawling. If you don't think you need more power then a 304 get the 4.0, if you really what a decent amount of power your gonna have to get something other then these two choices. 304's arent necaserily bad engines you just can't expect much more out of them then stock, one good reason is they have tiny cylinder head ports. I say get a tbi350 and have the best of all worlds

My vote is for the 4.0 with fuel injection. The engine is mostly bolt in but the 304 would also be pretty much a bolt in . Both will require exhaust mods but it will be much easier to adapt your current 6cylinder exhaust to the 4.0. The 4.0 will require fuel system mods but will run at any angle including upside down. cooling will be much easier with the 4.0 than any of the V8's. A downside to the 4.0 will be setting up the wireing harness and not having a big mess.

by the way I have a 93 Cherokee with the 4.0

The 4.0L I have in my tj kicks the crap out of the 304 I had in my cj I just sold. The cj had 33's and the tj has 35's and the tj has way more torque and horsepower. If you go v-8 make it worthwhile and go with a 383 chevy fuel injected.

Well I won't tell you to go 350TBI, or AMC 360 (although these would be better options) because you asked about the 304 or the 242. Between these two I'd go with the 242 (4.0). It is fuel injected already, makes 230 lb/ft of torque, and over 150 hp... not a lot, but enough for crawling. If you want more you can always swap the crank for a 258 crank. Then you'll get a lot more power. Go with the fuel injected engine... it's got close to the same amount of power, is easier to cool, and is fuel injected... you'll never have to tune it so don't worry about that...

I just took out my 304 that was balanced, blueprinted, bored .040 over, ported 401 heads, .262 cam, etc etc etc... it only had about 6000 miles on it. why?? the same reasons you listed.. it is mostly a rock crawler..I trailer it where ever i go. I have a 60 front and a 14 bolt rear and a tf727 with a dana 300 and 4.56 gears.
i'd be hard pressed to decide between an amc 401 and a fuel injected 2.5 but between a 304 and a 4.0 theres no question...i bought a 4.0 yesterday.

I'm running a 304 carburated with a 115 to 1 crawl ratio, the carb runs at any angle, the biggest advantage over EFI is I can idle down to less than 300 RPM and it still climbs, your EFI is still doing 700 to 900 RPM in the same situation which does not let you crawl as slow.

Originally posted by Rich T:
<STRONG>I'm running a 304 carburated with a 115 to 1 crawl ratio, the carb runs at any angle, the biggest advantage over EFI is I can idle down to less than 300 RPM and it still climbs, your EFI is still doing 700 to 900 RPM in the same situation which does not let you crawl as slow.</STRONG>


You can get an idle controller for the 4.0 to control the idle from 300rpm to 3000rpm Will be nice to have for rockcrawling or to idle up for airing up or welding. <IMG SRC="smilies/biggrin.gif" border="0">

OK, I'll throw my $.02 in here too. I have a 258 in my CJ with the Mopar MPI kit. I can't say enough good about this combo on the trail. It's runs at any angle, idles through damn near anything (I run 84:1 crawl) and has been very realiable. It sucks ass on the highway though. Slow as shit and bogs at almost every hill. Granted, the motor has 97K on it, and is stock except for the MPI. Given the choice between 304 and 4.0 for a trail only rig, I would go 4.0. You'll get better mileage, more torque (inherant with the inline design) and since it's already injected, it's gonna run no matter what.

If you were considering a SBC vs. the 4.0, well, that's a tougher choice.

Like someone else pointed out, grab yourself a 258 crank to throw in the 4.0 and make it a stroker!!!!

Another thing to consider, I have had a couple 304's, and a 360 that had low to zero oil pressure at idle and low rpm's, ad an uphill climb and it gets worse. Anyone else have this oiling trouble with the AMC V8's? BTW I'm running a Chevy 350 TBI now and no looking back <IMG SRC="smilies/biggrin.gif" border="0">

Originally posted by AGGIECJ-7:
<STRONG>
i dont know exactly what you have been
<IMG SRC="smilies/smokin.gif" border="0"> , but if you think that a CSB does not have torque, you are crazy....</STRONG>

i really wish people would quote everything i say, instead of clipping... my peak torque with my 360 is at 1500 rpm. what's the peak torque on a 350? around 2800, right? 2800 is midrange, 1500 is low end. yes, you can BUILD a SBC 350 to have low end, but from the factory, it doesn't have what an AMC v8 does. my 360 runs at about 330 ft lbs, as does a chevy 350.
chevy 350 stats (http://www.gm.com/automotive/gmpowertrain/engines_cartruck/vortec_silver/57_torque.htm)

anyway...

why get a 304? it's the same block as a 360, hell, the 360 actually weighs slightly less because it's been bored out.

BTW, AMC v8 heads are all the same, just as are the blocks. you get a head from a 304, it'll be the same head as on a 401.

if you're going to do a v8 swap, go bigger than a 304.

Originally posted by notcrazyjustnutz:
<STRONG>Another thing to consider, I have had a couple 304's, and a 360 that had low to zero oil pressure at idle and low rpm's, ad an uphill climb and it gets worse. Anyone else have this oiling trouble with the AMC V8's? BTW I'm running a Chevy 350 TBI now and no looking back <IMG SRC="smilies/biggrin.gif" border="0"></STRONG>

get new bearings. that fixes the problem on most engines. when you consider that the newest AMC engine is 10 years old, it's not too surprising that they're a bit worn out. i had my 360 rebuilt 10k miles ago and it runs like a gem.

Originally posted by WillyPete:
[QB]
BTW, AMC v8 heads are all the same, just as are the blocks. you get a head from a 304, it'll be the same head as on a 401.
QB]

survey says.... wrong!!!

Heads are different for 304, 360, and 401. they'll bolt up, but they have different valve sizes and rocker stud sizes. You dont want to run 304 heads on a 401.

4.0

Originally posted by The Flem:
<STRONG>survey says.... wrong!!!

Heads are different for 304, 360, and 401. they'll bolt up, but they have different valve sizes and rocker stud sizes. You dont want to run 304 heads on a 401.</STRONG>

I thought the 360 and 401 shared heads. I'm pretty sure they share valve sizes.

Wow, I'm surprised this is so lop sided for the V8! I absolutely love all 3 4.0 liter Jeeps I've had. Run at any angle, and GRUNT, damn, these things will run insanely slow RPM before they die! Their point of 80% torque is way low RPM too, I don't have the exact number in front of me. <IMG SRC="smilies/frown.gif" border="0"> By the way, the figures for horsepower and torque are 181 hp and 222 ft lbs of torque. I saw someone post a 150 hp number, and that's not correct.

I've also worked on my share of AMC V8 engines. I'm not a big fan of the design, and I HATE that aluminum timing/water pump/etc. thing on the front!

Sure, if you are all about show, getcha a V8, put some duals with glass packs on it, and go visit JU! <IMG SRC="smilies/smile.gif" border="0">

If you gotta go V8, do a collector and run single exhaust. The torque is way better than with duals, and you don't have to fawk with building an H pipe and making room for duals.

Originally posted by TornadoTJ:
[QB]
Sure, if you are all about show, getcha a V8, put some duals with glass packs on it, and go visit JU! <IMG SRC="smilies/smile.gif" border="0">

QB]

Hey now, don't knock the glasspacks <IMG SRC="smilies/thefinger.gif" border="0">

They are gone, its manifolds and mufflers for me. Still dual exhaust, but it has more than enough torque at idle to not stall off road, and thats with the sh!tty gearing of a 70's CJ

[ 10-31-2001: Message edited by: The Flem ]

I've had 258s in my wrangler and my CJ

I dont have much time on my v8 but the difference ins really noticable..

I run a 304 with standard exhaust manifolds and single 2 3/4s exahust and I pass the 4.0s going up the hills with out much o a problem..

There both decent motors. I just prefer the 8. I can bring my idle down to 300 with out it stalling no problem.. And I am carbed, it runs at all angles.

Use a late model 4.0L with Saudi calibrations; get one with JTEC, not SBEC (97 or later) to make it easy to program. It turns off most of the emissions so you don't have the check engine light.

Originally posted by The Flem:
<STRONG>survey says.... wrong!!!

Heads are different for 304, 360, and 401. they'll bolt up, but they have different valve sizes and rocker stud sizes. You dont want to run 304 heads on a 401.</STRONG>

you're right about the 304. i stand corrected. however, i know for a fact that 401 and 360 heads are interchangeable.

valve sizes for 304 are 1.787/1.406. the 360/401 heads will bolt onto a 304 block, i believe. 2.04/1.68 are the specs on the 360/401 heads.

Originally posted by John J:
<STRONG>Use a late model 4.0L with Saudi calibrations; get one with JTEC, not SBEC (97 or later) to make it easy to program. It turns off most of the emissions so you don't have the check engine light.</STRONG>

Can you explain? What's the difference between the pre '97 and post '97 ones?

Originally posted by apeters89:
[QB]If you want more you can always swap the crank for a 258 crank. Then you'll get a lot more power. QB]

What exactly do you need to do there? Anything else is needed? Any more info?

Chrysler changed engine controllers from SBEC to JTEC starting in 96 on Jeeps (and Dodge trucks and Viper). The JTECs can be re-programmed with a diagnostic scan tool (dealers often update the software in the modules for soft recalls or minor upgrades).

So if you can find a person with access to a dealer scan tool and can get the part # for a Saudi 4.0L, you can reflash the module with a less strict emissions package and gain some power in the process. This makes it easier to put late model engines in earlier vehicles.

Take a look under a YJ hood at its engine controller, then look at one under a TJ. You should see the difference.

I'm surprised no one has said anything about the problems with the computer crap with the 4.0. I've had so many problems with sensors and injectors and computers on my 4.0's and all you have to do is hop on NAXJA and read the OEM board and see how many other people have probs with the 4.0. I am building my YJ with a 258 at first just cause i have one but i think a old easy engine is easier than the new computer crap one JMO

You can check out one of the available Stroker Kits Here (http://www.accuratepower.com/Jeep/Stroker.html)

I haven't done the work myself because I already have the 258. All I need to do is swap on the MPI kit. Easier job, just more money...

Good luck!

Originally posted by apeters89:
<STRONG>You can check out one of the available Stroker Kits Here (http://www.accuratepower.com/Jeep/Stroker.html)

I haven't done the work myself because I already have the 258. All I need to do is swap on the MPI kit. Easier job, just more money...

Good luck!</STRONG>

Shit! I just peed all over myself. <IMG SRC="smilies/smile.gif" border="0"> I want it! Are there any other kits?