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So my Comanche has the 2.5 in it right now, ax4.  I got the Comanche as a second vehicle but also as a fun one. I want to swap out the 2.5 for something a little more rowdy. But I can't make up my mind. I have a Cherokee with the 4.0 so not really interest in just a stock 4.0 swap. So far on my list I have a amc 304, Dodge 318 magnum, and the AMC 4.2.  These choices bases on the fact I can use a ax15 and not worry about adapters and making trans mounts. The 304 would be cool but aftermarket support is limited(expensive) and it's measly output.  The 4.2 would be cool as I love the straight six, keeps it a tad different from just the 4.0, and has more speed parts than the 4.0 ( at least from what I've found) also it keeps it easy to swap as I don't have to worry about making motor mounts. Now the 318 is definitely the best for modifying but will be hard to get in. I've found some threads about it but nothing too concrete. Also alot of time devoted to making mounts. But these are super cheap and speed parts are the cheapest.  All of these will either be carbed or aftermarket fuel injection.  Not interested in 350/ls swaps, and I know it would significantly easier. Just looking for some feedback. 

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  • 3 weeks later...

Still undecided in this swap. Still keeping an eye out for a good 304, but now I'm kind of looking at the Chevy swaps. Man speed parts are Soo cheap for those compared to AMC and Mopar. Really don't want to do a 350 but I have been looking into a 327. A little different but just as 'easy' as a 350 swap. After thinking about it with the amount of GM that's been in jeeps it definitely fits the Comanches timeline better than a 318. 

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I put a Magnum 318 in my old ‘86 MJ. It was a little more than adequate for putting it down the road. :brows: The automatic behind it kinda killed some of the fun factor though. Always thought an AMC 360 would’ve been the real ticket. Left stock(ish) I don’t see why an AX15 wouldn’t last and you could use a cheap-o Howell style fuel injection to efficiently run it. 

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1 hour ago, neohic said:

Always thought an AMC 360 would’ve been the real ticket. Left stock(ish) I don’t see why an AX15 wouldn’t last and you could use a cheap-o Howell style fuel injection to efficiently run it. 

 

I actually kind of like the 360, even though it's a bit of a turd.  I think it's just the nostalgia factor.

 

Buddy of mine put a 304 in his YJ.  He admits it was mostly a waste of time/money.  I could have hooked him up with a 4.oh and cut down harness so he would make the same power and better fuel economy.

 

I've got a 360 out in one of my trash (parts only) J trucks.  I was told "it just needs a coil to run", so sometimes I get tempted to tear it out and see if it's even rebuildable.  It has some aftermarket bling on it too because the truck was used for mud racing (intake, carb, not sure what else).  Probably could make it scream pretty good on propane.  I doubt an AX-15 would be reliable behind it though, meaning there's not necessarily a ton of good/economical options at that point.

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6 minutes ago, Crash said:

IMO, Unless it's a 4.0L based stroker, swap in an LS-based engine.
Hopefully a 5.3/6.0/6.2 of a variety will get swapped in my MJ

 

I'd say that's the logical answer.

 

The reality is that the engine compartment is fairly cramped on the MJ, so most swaps are going to lead to some significant compromise.  Even the factory install of the 4.0L was a compromise on the cooling system.

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2 hours ago, DirtyComanche said:

The reality is that the engine compartment is fairly cramped on the MJ, so most swaps are going to lead to some significant compromise.

 

This is where I was at with my 318 swap when I did it. I didn’t want to cut my hood, do a mix and match to get an accessory setup that’d fit, or go with an aftermarket oil pan to get things lower in the frame. A 318 fits great! I had an AMC 360 on a stand that I could eye up at the same time. It came out of a J truck and the height/width was similar to my Magnum 318. I know one of those “wise old guys” that says he swapped a 360 into an ‘86 MJ at one time too. I also dig the nostalgic factor behind the swap. 

 

Besides... going with a 360 opens the door for so many future options! 390?... 401?!

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Yeah my goal is use the ax15 for sure so Novak has been my go too. Anything I put in it won't be left stock so I feel if I actually build the 360 the torque would be very close if not more than the ax15 limit.

 

The more and more I look at gm stuff I feel like that's the move. I mean I set of aluminum cylinder heads is 400 less than just 1 for the 360. 

 

I really wanted to keep it AMC or jeep but the budget and my fab ability says GM

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54 minutes ago, kansashogan said:

Novak's engine mounts are great. Super easy to install a sbc. I bought their radiator and it has had a couple leaks, grrr. If I had to do it over again I would go Ls. I think it would be overall much cheaper.

 

That's the problem with Novak, they build some good stuff that they got right, and they build some absolute trash that doesn't work at all.

 

Their entire LS swap package falls into the trash category.  Motor mounts that fail in short order, radiators that are expensive and leak, headers that are ridiculously overpriced and are basic bare steel, ECM tuning that probably won't ever even run decently...

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I'd go the LS route. I know it's not what you are wanting to do, but there's a reason it's so popular. Cheap, tons of power and has been documented for swaps. 

 

Are you looking for the destroked 350-->327 or you taking about the actual 327? 

 

 

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6 minutes ago, JustEmptyEveryPocket said:

Or think WAY outside the normal box and do something like THIS. One year I will be swapping a TDI into one of my MJs. Power, fuel economy, cool factor, space, weight, AX-15 tranny, etc. It ticks all the boxes.

 

At this point I will say I regret not going with a TDI versus the OM617.  I had reasons for leaning towards the OM617, but unfortunately I have realized that some of my original research was wrong, and some of the assumptions I made turned out to be far worse in actuality.

 

 

Spoiler for anyone...  I'm probably going to put the OM617 in my J10 based on where I am at with it in the MJ chassis, versus where I would like it to be.

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I will build my own engine and trans mount, Xmember. 

 

What I've been waffling on is what engine/trans combination. 

 

Manual is a MUST!,  I'm not giving up my stick. 

 

I don't like Novak or AA options.........not at all, particularly with the slaves. 

 

I'll have more options for radiators with the 2.5 rad support.........you 4.0 guys ought to look at that. 

 

As mentioned.........Sanderson huggers............non issue.

 

I spoke with the performance rep at Rockland Standard today about the Tremec TR 6060 4X version today, pretty sure I'm going this route, pricey at $5700 but........

https://www.rsgear.com/products/off-road-truck-transmissions

 

 

I found my bare block today, 1st Gen 350, 4 bolt, standard bore for $25. I'll pick it up on Monday. 

I stopped at a machine shop in another town to see if they had any blocks for sale, this one needs a line bore, spun bearing. I should have just picked it up but I wanted to make sure that the machine shop I deal with would line bore at a reasonable price.......$150, so I called the other shop and told them I'd come back on Monday. 

 

No LS, No adapters. No BS. 

 

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Well alot to read on here. Didn't know Novak was so spotty. I have there shifter cable for the Cherokee and it's awesome, so I assumed pretty much everything they make is good enough. 

 

I meant the original 327, thought it would be a good little motor.  High compression build and all. 

 

Definitely sticking with gas. This is gonna be a street/strip truck. 

 

Same as Jeepdriver, definitely keeping it a manual. That's the main reason I got this truck, other than the fact I love jeeps 

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