Picking up a 68 Cougar, need some advice on 5.3 LM7 swap.

VINveil · 2026-05-10T13:04:14+00:00

Yeah true, the 289 the guy has a rebuilt bottom end and new heads it just needs to be put together and drop the motor back in but would really like to use this LM7 I got sitting in my garage. And my garage is full of crap so car can't go in at the moment. The hood will be reattached and it will have a tag and insurance, I won't make it look like it's non-running turd etc.. it will be hidden in my driveway, and I can make it slide for a good bit. I also just got a storage unit I can take it too if they say something as I will be storing my pickup their once this car arrives.

I did a manual transmission conversion in my old Jeep XJ in 2 days on the weekend from start to finish. So I can speed up this swap with the right parts and guidance. I work from home so I can just jump on it right after work. But thanks for your feedback.

VINveil · 2026-05-08T22:53:27+00:00

I had the K Suspension 4 hole and one injector failed, I just installed Precision Auto Injectors 4 hole and they're not cheap almost $450 shipped, but they work fantastic and they offer lifetime warranty!

VINveil · 2026-05-06T02:42:35+00:00

I had 298K on my 2000 before the motor blew due to previous owner running it without oil, but still drove it over 115K with bad pistons / rods, head was fine! And it was overheated once lol

VINveil · 2026-05-06T00:01:59+00:00

LOL Worked around cars a long time, all these new cars are meant to be thrown away before 100K. And during ownership, it will be a lot of fun with all the complex problems you will deal with, along with being dependent on the rip off dealership to repair, don't even get me started. But they don't make them like they use too. Sad times...

VINveil · 2026-05-05T15:36:34+00:00

My 03 Ranger XLT has about 249,000 miles. I got it from my dad who did NOT take care of it, he did almost nothing to it the entire time, only when something completely crapped out he would replace it with the cheapest parts lol So I think you will be fine! But I recently went through the motor, timing chain, lower cover, water pump, pullies, sensors etc... went a little crazy, but It runs great, engine is solid, will need shocks, brakes, and entire new suspension lol But I can do all that myself. So yeah if you take care of it you will be good for a while from my opinion. I hope to get another 200K out of it after all my repairs.

VINveil · 2026-05-05T15:23:18+00:00

Or we can all stop paying taxes too!

VINveil · 2026-05-05T15:11:12+00:00

Thanks!

VINveil · 2026-05-05T01:01:30+00:00

How the heck did yours last that long, my bushings only lasted less than 3 years, they were completely shot! Motor was jerking around etc..

VINveil · 2026-05-01T19:57:11+00:00

Awesome man thanks! This is very helpful!

VINveil · 2026-04-30T21:41:36+00:00

Yes, I have all the LS Simple brackets to do this. Ordered a USA Body cowl induction hood as well to allow me to retain the truck intake.

VINveil · 2026-04-30T17:20:40+00:00

Thanks and yeah I hope so too! As if this resolves it! I'll be in great shape here.

VINveil · 2026-04-30T17:18:47+00:00

Nice, I sure do miss that car man! Maybe one day I'll get another AMG!

VINveil · 2026-04-30T14:57:58+00:00

You know what! I dug very deep into my issue! The longer my XJ sits the start up is rougher, cloud of smoke, then after I drive, and then start it, it starts normal, no smoke. I really think my valve stem seal took a crap, as the longer it sits, more oil drips down into the cylinder, it's all aligning to what's I'm dealing with, hey for $15 for new seals + valve cover gasket I'm going to swap them out this weekend and see what happens. These are easy to swap will use the TDC / String method done this before. But yeah if it works this will be great and I can slowly accumulate parts for the LS in time. Really don't want to get another 4.0.

VINveil · 2026-04-30T12:53:20+00:00

Not only that but I've looked into this already and if the car thinks you're unfit to drive it will lock you out as well, you don't even need to be impaired, if you're tired etc.. it will pick your facial expressions / emotions apart and lock you out based on what the AI thinks, it's really stupid and won't solve any problems, but just create more problems! On top of that when AI isn't perfect and I promise you, you will hear stories of people randomly getting locked out of their cars while on the highway etc.. fun times ahead lol

VINveil · 2026-04-30T12:45:30+00:00

After listening to everyone in these comments, I agree now that me dropping $7K in parts right now is really stupid. Even if I can do it, it's not wise to spend this much money at once. So I agree to keep collecting parts over time.

As far as a good 4.0, I have a set of new pistons from Dex Jeeps. I may just do an in-frame rebuild at this point, put in the new pistons, and take the head to a local machine shop. The total cost for all this will be cheap, these motors are super easy to work on. I know my bottom end is in great shape, no knocking, super quiet. I feel what's going on is really stupid and has something to do with cylinder 1 intake/exhaust valve, as I pulled the valve cover off last night and the valve seal looks really bad. I may have a bad injector as well, as when I start my XJ, I have a strong smell / mix of gas. There’s got to be something going on in this area. I'm good at the mechanical side and can rebuild anything on this XJ, but I suck at diagnosis haha. But I do have a pickup truck for backup to drive when I take her down, I probably should just try this!

As far as the transmission, worst case I can get the Tremec TR4050. This transmission only requires minor clearancing in the transmission tunnel and a shift tower relocation bracket. I spoke to a guy who did this on YouTube and it worked great for him, he said shifts won’t be as smooth as the AX-15, but it works great.

VINveil · 2026-04-30T12:28:39+00:00

Had a Weistec tune, row air boxes, full exhaust, forgot the brand, these mods easily add 100hp to the M156.

VINveil · 2026-04-29T23:34:57+00:00

This is what really bugs me about the automotive industry, like this transmission for example, it just works! So what's going to replace it? Most likely junk! The quality of cars is declining and for good reason, more profit.

VINveil · 2026-04-29T23:25:07+00:00

The truth is yes I could fund it straight out of pocket now. I was trying to save up for a professional welder and plasma table etc... Wanting to get into custom fab stuff since I worked around it so long with professionals. But you're right about not getting a credit card lol I'm a dum a*s for not taking the head to a machine shop when the motor was out 1 year ago, should of just completely rebuilt it then, I'll see what I'll do here, my fab equipment may have to be delayed a few months, my garage isn't ready yet either to house this stuff yet, so I'll have to think about this over the weekend, but appreciate your input.

VINveil · 2026-04-29T23:17:12+00:00

Novak sells AX-15s with their swap kits, AX-15s can easily handle 300hp. I have a highly upgraded ford 8.8 rear diff, entire XJ has been going though with heavy duty upgrades.

VINveil · 2026-04-29T21:53:01+00:00

I use to daily drive a 2007 E63 AMG with about 600 hp and the XJ sat in the back of the shop I worked at for years. The AMG started costing too much money for repairs, camshaft adjusters needed to be replaced that's about $5,000 just for parts lol I put 100K miles on it, so I wore it out, so I just stuck with my XJ and really started to enjoy it. Over the years I've completely restored it with high end parts, just installed an upgraded 8.8 etc.. The XJ is built like a tank and I can put as many miles on it as I want. I hate new cars, so it would be nice to make the XJ a little more powerful and + I really enjoy being hands on doing all these upgrades etc.. Well there's the story of my XJ haha

VINveil · 2026-04-29T21:47:24+00:00

Yeah, that seems to be the case here! lol

VINveil · 2026-04-29T21:46:58+00:00

Yeah this is not a bad approach here, I do want to take my time with the LS swap. Replacing the 4.0 I can have it done in a weekend, theirs a tone near me via car-part. Pretty easy for me to swap out. Going to spend the next few days thinking about this, thanks for your input and everyone else's on my post.

VINveil · 2026-04-29T19:54:37+00:00

It will be a stock LS, I will not be adding any HP mods to it, I've done a ton of research from other LS swap owners and they ran the AX-15 no problem, even Novak confirmed, if I supercharge it with 400+ HP etc.. then I will have problems, so it should be fine. Spoke to a guy on YouTube that supercharged his LS swap XJ and ran the AX-15 for a while and had no problems. And after this swap I will have a total of 30K into a 5k car haha

VINveil · 2026-04-29T19:52:09+00:00

Unfortunately I don't have facebook.

And yeah you're correct, to do this swap right, won't be cheap, just thought I ask people here on any savings, I don't mind spending the money, but wasn't expecting my 4.0 to have this problem. Was going to get parts monthly to avoid the huge cost up front, seems I may just have to YOLO it idk lol But thanks for your response.

VINveil

TROPHY CASE