1991 grand wagoneer 5.3 motor only swap

For everything related to using Fuel Injection in an FSJ.
Post Reply

Topic author
Jeepfamily
Posts: 4
Joined: Sun Dec 12, 2021 6:06 pm

1991 grand wagoneer 5.3 motor only swap

Post by Jeepfamily »

I had been contemplating on what to do with my grand wagoneer for a couple years. Back story is my grandfather bought it used in 1993 and drove it til the day he died(almost literally). My grandmother drove it during the Idaho winters for another 10 years or so before she ended up in a nursing home. I bought it from her and got a one way plane ticket to Idaho and drove it home to Oregon. I've had it for 4 years now. Total miles on the clock 136000.

Everything on it was original and everything works except the overhead compass/temp display. I drove it every once in awhile as I had other vehicles. This last year we paired the fleet down to one family vehicle and the jeep(much to my wife's displeasure, shes not a fan of the jeep). Being that it's a "rare" 91 final edition I wrestled with keeping it stock or modifying it. I finally got tired of being eye to eye with Subaru owners at stop lights and lifted it 4" and put 31's on it.
https://www.flickr.com/photos/195173040 ... ed-public/

Now the original 360 ran ok but was gutless with 31s(stock 3.31 factory gearing) and was showing it's age. It leaked oil from every seal, the carb needed rebuilt, the alternator was starting to intermittently not work, and the starter was in the same boat. The nail in the coffin was it vapor locking on me during a 90+ degree summer day while going over the cascade mountains for a camping trip. So I started planning.....

I wrestled with rebuilding the 360 and putting the Edelbrock pro flow efi system in it. Approx cost was estimated around 5500$ depending on what all the engine needed during the rebuild. My issue is I'd still be stuck with a turd of a motor that used cork gaskets for everything....not ideal. So I looked into what a 5.3 ls swap would cost. I didn't want to do the entire drivetrain swap like everyone else does as my trans and tcase work fine. Also wasn't fond of trying to make a 3spd column shift work with an od trans and the other ways I've seen tcase levers done. I don't really care about mpg as I don't drive it every day. So I researched as much as I could. Called a few vendors and they thought I was nuts! I saw forum member dodgerammit post about doing the same swap successfully so I pulled the trigger and collected parts. I kept a running sheet of cost totals and marked a date on the calendar to start with the hope of having it running quickly.

The day came and a buddy and I tore into it. I'm an ex Chrysler master tech and my buddy is a diesel tech. We didn't pull the fenders or front core support like everyone else does. Just the hood and did the whole thing in my garage. Had the old engine out and the junk yard sourced 5.3 from an 01 Tahoe bolted in a day and a half. I used flying iron fab motor mounts and the advanced adapters transmission adapter and it all slid right in without any issues. I worked on the actual hard stuff for about 6-8 hours a day for a week. I put a 97 blazer 2 door tank and pump in the back and deleted the oe saddle tank. Ran -6 an ptfe fuel lines, made a custom fuel fill adapter as jeep hoses are 1" and the blazer tank was 2", had a custom ps pressure line made, had to figure out custom radiator hoses as I reused the original jeep radiator. The jeep mechanical fan bolted up to the Chevy mechanical fan clutch after resizing the holes. I used the harness and pcm that came with the engine and wired in the required relay/fuse panel. Had lt1swap.com flash the pcm, also their website was a godsend of info for the wiring. Used the original 5.3 exhaust manifolds and we made a custom down pipe that hooked up to the oe jeep cat and muffler using prices of the jeep and Chevy down pipes. Installed adapters on the engine to run the jeep oil psi and coolant guages using the oe jeep senders. There's more I'm sure I'm forgetting feel free to ask.
https://www.flickr.com/photos/195173040 ... ed-public/

In total it took 1 full week and another week of working a couple ours a night on it......and it runs and drives! Holy crap what a difference! Power whenever you need it! It does burnouts now! I can get in and start it up dead cold and just...drive...away... without hiccups! I've put 40 miles on it so far and am taking it for a couple hundred mile trip over to eastern Oregon for some much needed dirt bike therapy this weekend so we will see how she does. I'll report back. Also, total cost including the engine...4000$ not too bad(even includes having the rear driveshaft lengthened/rebuilt). I'll post pics once I figure out how to do it. Let me know if you have any questions!
You do not have the required permissions to view the files attached to this post.
Last edited by Jeepfamily on Thu Mar 10, 2022 9:18 pm, edited 5 times in total.
User avatar

Yeller
Posts: 1521
Joined: Thu Apr 01, 2021 7:54 am
Location: Rogers County Oklahoma

Re: 1991 grand wagoneer 5.3 motor only swap

Post by Yeller »

I’ve done the same basic build as you a few times. It’s so nice to be able to just drive our vehicle, it just makes it so much more enjoyable. I have about 200 miles on my j10 swap and am taking it on an 800 mile road trip this coming week.
The bus I ride is so short it is a yellow Smart Car full of squirrels, monkeys and clowns.

1970 J2500 Resto Mod
https://www.fsjnetwork.com/forum/viewt ... 12&t=21395

1974 Bronco “Broncno”
https://classicbroncos.com/forums/threa ... st-3411909
User avatar

dodgerammit
Posts: 1434
Joined: Wed Jan 11, 2017 11:20 pm
Location: Middle TN

Re: 1991 grand wagoneer 5.3 motor only swap

Post by dodgerammit »

Jeepfamily wrote: Fri Mar 04, 2022 12:30 am I had been contemplating on what to do with my grand wagoneer for a couple years. Back story is my grandfather bought it used in 1993 and drove it til the day he died(almost literally). My grandmother drove it during the Idaho winters for another 10 years or so before she ended up in a nursing home. I bought it from her and got a one way plane ticket to Idaho and drove it home to Oregon. I've had it for 4 years now. Total miles on the clock 136000.

Everything on it was original and everything works except the overhead compass/temp display. I drove it every once in awhile as I had other vehicles. This last year we paired the fleet down to one family vehicle and the jeep(much to my wife's displeasure, shes not a fan of the jeep). Being that it's a "rare" 91 final edition I wrestled with keeping it stock or modifying it. I finally got tired of being eye to eye with Subaru owners at stop lights and lifted it 4" and put 31's on it.

Now the original 360 ran ok but was gutless with 31s(stock 3.31 factory gearing) and was showing it's age. It leaked oil from every seal, the carb needed rebuilt, the alternator was starting to intermittently not work, and the starter was in the same boat. The nail in the coffin was it vapor locking on me during a 90+ degree summer day while going over the cascade mountains for a camping trip. So I started planning.....

I wrestled with rebuilding the 360 and putting the Edelbrock pro flow efi system in it. Approx cost was estimated around 5500$ depending on what all the engine needed during the rebuild. My issue is I'd still be stuck with a turd of a motor that used cork gaskets for everything....not ideal. So I looked into what a 5.3 ls swap would cost. I didn't want to do the entire drivetrain swap like everyone else does as my trans and tcase work fine. Also wasn't fond of trying to make a 3spd column shift work with an od trans and the other ways I've seen tcase levers done. I don't really care about mpg as I don't drive it every day. So I researched as much as I could. Called a few vendors and they thought I was nuts! I saw forum member dodgerammit post about doing the same swap successfully so I pulled the trigger and collected parts. I kept a running sheet of cost totals and marked a date on the calendar to start with the hope of having it running quickly.

The day came and a buddy and I tore into it. I'm an ex Chrysler master tech and my buddy is a diesel tech. We didn't pull the fenders or front core support like everyone else does. Just the hood and did the whole thing in my garage. Had the old engine out and the junk yard sourced 5.3 from an 01 Tahoe bolted in a day and a half. I used flying iron fab motor mounts and the advanced adapters transmission adapter and it all slid right in without any issues. I worked on the actual hard stuff for about 6-8 hours a day for a week. I put a 97 blazer 2 door tank and pump in the back and deleted the oe saddle tank. Ran -6 an ptfe fuel lines, made a custom fuel fill adapter as jeep hoses are 1" and the blazer tank was 2", had a custom ps pressure line made, had to figure out custom radiator hoses as I reused the original jeep radiator. The jeep mechanical fan bolted up to the Chevy mechanical fan clutch after resizing the holes. I used the harness and pcm that came with the engine and wired in the required relay/fuse panel. Had lt1swap.com flash the pcm, also their website was a godsend of info for the wiring. Used the original 5.3 exhaust manifolds and we made a custom down pipe that hooked up to the oe jeep cat and muffler using prices of the jeep and Chevy down pipes. Installed adapters on the engine to run the jeep oil psi and coolant guages using the oe jeep senders. There's more I'm sure I'm forgetting feel free to ask.

In total it took 1 full week and another week of working a couple ours a night on it......and it runs and drives! Holy crap what a difference! Power whenever you need it! It does burnouts now! I can get in and start it up dead cold and just...drive...away... without hiccups! I've put 40 miles on it so far and am taking it for a couple hundred mile trip over to eastern Oregon for some much needed dirt bike therapy this weekend so we will see how she does. I'll report back. Also, total cost including the engine...4000$ not too bad(even includes having the rear driveshaft lengthened/rebuilt). I'll post pics once I figure out how to do it. Let me know if you have any questions!
Yep, I did the same with mine. 4.8, Adapter, freshened 727. Stock 2.72 and 235/75/15s with stock height. Put over 1000 miles on it since. Even have daily driven it for the last 2 weeks. The difference in the hp rating makes a huge difference on the pick up even with the 2.72s. She's not quick, but will keep up with in town traffic good enough now. Since the motor was DBC, I used the Lokar 727 kickdown cable to control the trans and adapted it to the throttle body.

FWIW, I'm getting 16mpg in town. Right on par with all the full drivetrain swap guys. And I kept my stock driveshafts. They may best me by 1-2mpg on highways, but with the last fill up, I'm now thinking it's not as likely as I thought.

Our costs were about the same. Also have about $4K in mine.
84 Grand Waggy-Radio Flyer (Garnet Red/3M Ebony Metallic woodgrain, with honey interior) AMC 360 :cry: 2004 4.8LS/Advance Adapter/727/242 D44/AMC20 Serehill tailgate and headlight harnesses :fsj: Ongoing thread-viewtopic.php?t=11897

92 Wrangler Islander 4.0/32RH/231 D30/D35 RHD

Topic author
Jeepfamily
Posts: 4
Joined: Sun Dec 12, 2021 6:06 pm

Re: 1991 grand wagoneer 5.3 motor only swap

Post by Jeepfamily »

Just got back from my trip. 240 miles round trip. Towing a 2400# trailer with 500 pounds of guys and gear from 500 feet to 5000 feet to 3000 feet and back. 11mpg. I was impressed. Only had to kick it down to 2nd for the steepest grades. Much improved over the old 360. I had to have my rear driveshaft extended as the splines were showing on the slip shaft at ride height. Likely due to my 4" lift and the ls motor mounts positioning the motor at least an inch lower than the original 360 which pointed the tcase up.
User avatar

dodgerammit
Posts: 1434
Joined: Wed Jan 11, 2017 11:20 pm
Location: Middle TN

Re: 1991 grand wagoneer 5.3 motor only swap

Post by dodgerammit »

Jeepfamily wrote: Sun Mar 06, 2022 11:03 am Just got back from my trip. 240 miles round trip. Towing a 2400# trailer with 500 pounds of guys and gear from 500 feet to 5000 feet to 3000 feet and back. 11mpg. I was impressed. Only had to kick it down to 2nd for the steepest grades. Much improved over the old 360. I had to have my rear driveshaft extended as the splines were showing on the slip shaft at ride height. Likely due to my 4" lift and the ls motor mounts positioning the motor at least an inch lower than the original 360 which pointed the tcase up.
That is great news! :-bd I'm looking at switching to a 1600# teardrop for camping duties, so the 2.72s should do decent.
84 Grand Waggy-Radio Flyer (Garnet Red/3M Ebony Metallic woodgrain, with honey interior) AMC 360 :cry: 2004 4.8LS/Advance Adapter/727/242 D44/AMC20 Serehill tailgate and headlight harnesses :fsj: Ongoing thread-viewtopic.php?t=11897

92 Wrangler Islander 4.0/32RH/231 D30/D35 RHD

Topic author
Jeepfamily
Posts: 4
Joined: Sun Dec 12, 2021 6:06 pm

Re: 1991 grand wagoneer 5.3 motor only swap

Post by Jeepfamily »

Update. Been driving it around a fair bit. Did a drive yesterday. Mostly highway 55-60 mph going from 500ft to 1500ft with about 300lb of gear in the back. Round trip I got 16.4 mpg. Not too shabby!
User avatar

dodgerammit
Posts: 1434
Joined: Wed Jan 11, 2017 11:20 pm
Location: Middle TN

Re: 1991 grand wagoneer 5.3 motor only swap

Post by dodgerammit »

Jeepfamily wrote: Sun Apr 03, 2022 8:17 pm Update. Been driving it around a fair bit. Did a drive yesterday. Mostly highway 55-60 mph going from 500ft to 1500ft with about 300lb of gear in the back. Round trip I got 16.4 mpg. Not too shabby!
Right about what I'm getting. :-bd Swapping out the transfer case in mine and doing rear wheel bearings/seals in preparation for a vacation trip next month.
84 Grand Waggy-Radio Flyer (Garnet Red/3M Ebony Metallic woodgrain, with honey interior) AMC 360 :cry: 2004 4.8LS/Advance Adapter/727/242 D44/AMC20 Serehill tailgate and headlight harnesses :fsj: Ongoing thread-viewtopic.php?t=11897

92 Wrangler Islander 4.0/32RH/231 D30/D35 RHD
Post Reply