83 cj7 engine swap question

[psylocke1983cj7]

I was thinking about swapping out my 258 I6 for a 304 v8 engine. Does anyone have any advice on doing this. I've been looking around the internet trying to find info on how to do this. I currently have a T-5 transmission, will I need to buy an adapter for the 304 or something else?

- psylocke1983cj7

 

[avyoung]

Factory Driving Lights

If you are going to go with a V8 make it easy on yourself and go with a Chev 350. It will be cheeper and run better in the end. The 350 swap is very popular so you should be able to get adapters very easily.

 

[Junkpile]

How will it be cheaper and run better in the end?

 

[derff96963]

The 304 would even be marginal with the stock transmission and axles. You put a 350 behind a T5 and you are just asking for trouble. It can be done but I just would not recomend putting all that work into an engine swap and have to do it all over again since you ripped out the transmission.

As for the 304 it could be done it would bolt right up to the transmission you have and if you are easy on it you might be ok. You would need to get the right engine mounts for it and possible a new Radiator if you have the 1 row one. Other than that just wiring. And Keep in mind that engine is going to weigh a goot bit more.

 

[avyoung]

Cheeper because 350's are a dime a dozen, Parts are easy and cheep, they are very reliable, in 10 years when you can't get parts for the 304 you will end up swaping in a 350 anyway.

 

[redrooster]

How will it be cheaper and run better in the end?

I don't even want to discuss how much I spent on that 360 I swapped into my Jeep. Do yourself a favor and swap the Chevy motor in there. You can put a rebuilt 350, transmission of your choice and transfer case in for what the Jeep motor alone will cost to build.

 

[derff96963]

May I ask why it costed you do much. The last time I was at the junk yard here I found 4 360's in about 20 minutes. That Yard sells engines for $200 as is no matter what. it does't cost that much to get one rebuilt. Besides he wants to put a 304 in and not a 360.

 

[redrooster]

I wanted it to be 100% rebuilt (meaning rebuilt heads, new crank and cam), so I bought an assembled long block and took all the components off the 304 and put them on the 360. They are all interchangeable except heads and block.
By the time that you buy the engine, rebuild it, replace the expensive timing chain cover and oil pump assembly (which should be mandatory), and call around for all the little B.S. that the yard didn't give you, I guarantee that you could have bought a running 350 and adapter.
I added fuel injection, and DUI ignition (which is a GM HEI with a hot coil pack) and that really racked up.
What I should have done is bought the $200 adapter and bought a junkyard throttle body 350 for $800 and then all I would have left to get would be harness (and fab up some motor mounts).
At the time I wanted to stay Jeep, but now I just want things that are readily available for quick repairs. Shipping charges from Quadratec every other day for misc parts gets old.
You can swap in an AMC V-8 cheaply if you have the donor vehicle sitting right there and you know it runs and is in good shape. Otherwise save yourself the headache.

 

[derff96963]

Well I understand what you are saying. However is all depends on how quickly you want to get the job. As with anything you look long enough and you will find what you need cheap. When I did my swap from a 4 cyclinder to an I6 I needed to get the bellhousing for that engine and my transmission. I have the T176 and I could not find a bellhousing at a junk yard anywhere. I could get a new one of the internet for over $250 by the time I got the spacer plate and shipping. I just waited and 3 weeks later I friend suggest a junk yard he herd of, It was 20 miles away but they had it and I got it all including the bolts and spacer plate for $35. It was well worth my time and gas to do that one. I understand that a 350 would be cheaper to get the engine but then you need a new transmission because it would not be the best idea to put a old T5 behind a 350. You will also need to replace the axles too. You just need to look at your options and decide what you really want to do with your jeep. And if you got the time to find what you need.

 

[Junkpile]

Air lines

avyoung and redrooster----- well, how much did it cost you guys when you did your Chevy 350 swaps?.........because when I did my buddy's, it cost more than the BUILT AMC swap I just did. Machine work cost the same on each block, the AMC heads required less work to flow a decent number, and there were NO adapters involved. If you actually price the components involved in rebuilding an engine that has no major damage, the Chevy isn't THAT much cheaper.

As far as them not making anymore parts for AMCs.......maybe you send a letter to Edelbrock because they just wasted alot of money developing that new fuel injection system and aluminum heads they just came out with. Pontiac made it's last V8 in 1981 and there are lots of parts still available for that engine and they come out with new ones every year. What engine was it they were still using in the Grand Wagoneer right up until they killed it? I can still find rebuild parts for Ford flatheads.......they stopped making those long before AMC even started making 304s and 360s.

 

[cra034]

I would suggest why are you looking to dump your 258, certainly not for the torque. I nice rebuild with 4.0 heads would be a good start. And Clifford has many fine hiperf goodies, i.e. cam, manifold or even fuel injection. I think V8's are overated.

 

[derff96963]

That us very true cra034. I completely forgot about that. Cilffords Motto is 6=8. What they claim is that if you swap the camshaft Header, and Intake to thiers you can get the same horsepower as a v8 out of your 6 cylinder. This has huge benefits since you don't have the weight of the V8. That gives you the extra extra performance. Just somthing to think about and look into.

 

[redrooster]

Powertrax no slip locker

This has huge benefits since you don't have the weight of the V8.

I don't know about a big weight difference, the 6 is a huge chunk of cast iron.
Junkpile...I guess it depends on what you are trying to build. As far as picking up a used AMC and rebuilding one, it can be pricey. You may be fortunate enough to get one that runs.
Around here, you can go to a Junkyard and get a Chevy motor with a 90 day warranty. Throttle bodies are around $800, Vortecs for a $1000, and LT1's for about $1200. They will pull them as complete as you want. Usually all you have to do is get a new wiring harness and modify your motor mounts. Most guys go ahead and put a chevy transmission on at the same time. Either an SM465 or TH350 and then use an NP205 or adapt it to a Dana 300.

 

[avyoung]

I have not done a swap on my jeep. I learned my lesson on my 63 IH scouut I had in highschool. It had a slant 4 I wanted a v8. I bought a complete doner and came to find out the IH 304 is a big block. That swap took me all year in shop class and I still didn't finish it. The old S4 kicked but off road but I wanted a little more on road. That is one of the worst mystakes I ever made. I could have swapped a chev motor with 1/2 the work and cost. Yes I know you are working on a Jeep and it is a differant beast I am just telling you my experiance.

You have to look at what you want out of you rig. If you are going to keep it for a while then you want to start with a fresh motor (rebuilt) why throw a motor in with 150000 miles and have to yank it later. Parts for a 350 are a lot cheeper than anything out there that goes for performance or replacement. You can get over 300 horses out without much trouble at all. Now don't get me wrong I run the original I6 in my 5 and have no plans of changing it. I don't mind doing 60 on the highway and not worrying about breaking parts with a V8. All I am saying is think about options before you do what I did and pay a fortune for a swap that was not that great in the first place.

 

[Junkpile]

If the only place you guys have to buy parts is a catalog full of aftermarket stuff.......well, okay the Chevy might be cheaper.

I'm a little confused about the comments "I guess it depends on what you are trying to build" and "You have to look at what you want out of your rig". Am I to assume my Jeep is less capable in the engine department than a guy with a 350? I don't think so.....at least not any guy with a half worn-out $1200 junkyard LT1. I'm not trying to be an A-hole or anything, and I am NOT an expert by a long shot. I love Chevrolets. The AMC is a misunderstood animal though. A 390 or 401 AMC has a forged crank and rods straight from the factory, that's big money in a Chevy. All AMC dogleg exhaust port, big valve heads will flow more than all but the most modern high tech Chevy heads, that's another BIG money difference in the AMCs favor. AMCs have large diameter lifters, so a properly ground AMC cam will allow more valve lift than a Chevy grind of the same duration. AMC heads have canted valves. Heavier castings allow more radical machining of certain components. AMCs are high nickel content castings, very rigid and less prone to wear and core shifts that require more expensive machining processes during a complete rebuild. Stronger bottom ends.
My 304 block is a completely factory 7x,xxx mile unit from a junkyard 1979 CJ5. Like most junkyard AMCs with less than 100,000 miles, it didn't require anything more than a new set of rings and bearings, an oil pump and timing chain, and a complete gasket kit $350. There is around $800 invested in my junkyard 79 360 cylinder heads. $320 for cam, lifters, and pushrods. Used edelbrock R4B intake manifold $20.00. $175 for headers. A couple hundred more for new engine mounts and various other parts.
Now, after I buy that $800 junkyard warranty 350......how much more is it going to cost to install? Then, how much more to make it where it will outrun my dads 2000 Bullitt edition Mustang, like my 304 pushing 36s does? :wink:

With that said....a 350 swap is sweet, but it's not the only option and it's not always the best option.

 

[avyoung]

I agree! I was just saying look at all the options before you decide on what is best for you.

 

[redrooster]

Then, how much more to make it where it will outrun my dads 2000 Bullitt edition Mustang, like my 304 pushing 36s does?

You were sounding pretty credible until you made that B.S. statement. If you can outrun a Bullitt Mustang then you need to tell your dad to try putting it in gear.
My wife had an '03 Cobra and there isn't a Jeep made that could outrun that thing even with a supercharger.
Just from adding the figures you have above you total up to $1665 without the price of the block or misc. parts, and you still don't have a fuel injected motor. All that power ain't gonna do you much good with black smoke boiling out of the exhaust and the engine trying to stall on a hill.
Since the subject has drifted to a challenge of horsepower, the last LT1 I witnessed being installed came from a Junkyard with the 90 day warranty and supposedly only had 45,000 miles on it. I don't think that qualifies as being worn out. Now granted an LT1 is going to cost you more due to the expensive harness, but I've got money that says any 304 short of having nitrous can't hang with an LT1. The LT1 is not the torque monster that the 401 or maybe even 360 is but most guys around here substitute that with 6.72 geared rockwells or 4 to 1 kits.
I still run my 360 and like it. They are good running motors if built right and very strong too. I will never run another one though because of the issues we have discussed before and the availbility of parts.
Anyway, I hope that somewhere in our debate of AMC vs. Chevrolet that we have helped you gather some insight on what you want to do under your hood.

 

[cra034]

Wow looks like psylocke opened a can a worms with that question. Sounds like Junkpile and Redrooster need to go wheeling together and have fun. Also sounds like Junkpile knows his stuff and can probably build a badass 304 that would kick a Bullitt in the butt. Quite frankly I don't see how you compare a Bullit to a Cobra. I believe bottom line is AMC in AMC is easier and more dependable. Chevy motors rock but it's not the cheapest route.

 

[fourtrail]

Re: Wheelin' in WV

I have seen and been part of both swaps. I am not bias toward either one, I am putting a 318 mopar in my next Jeep. Both swaps have their place, the 350 swap we did was with a motor we had laying around and got a good deal on a bellhousing from a 4 cyl and installed it in front of the factory T-176, which has had no problems behind the 300 HP 350. Bolt in motor mounts are availible for both motors and while a Chevy is cheaper to build if you already have an AMC motor you don't have the core cost. It depends also what motor was already in there, AMC v-8 will bolt back to the 6 cyl bellhousing, while a 350 will bolt to the 151 4 cyl bell housing with a small amount of work. It really doesn't matter what motor you put in as long as you are out having fun with your Jeep This is the important part, not bickering over what motor is better. It is just as petty as the round eye-square eye debate. Just my $.02

 

[Junkpile]

Hey, I'm not trying to argue. I'm sorry if I gave that impression, but I have had this conversation at least 20 times. I love ALL Jeeps. I ran a 2.5l for a long time and loved it after I learned how to handle it. It's all good. No problems here.
I enjoy this message board and I have learned alot from it, I don't want any of you to think I am a jerk or anything......so if I gave that impression I appologize.

It really does outrun the Bullitt in the 1/8 mile.