GM 5.3 swap questions

[Grand_Wag_85]

I'm planning out a future GW build and all of this talk about GM 5.3 swaps lately has got my attention. I see a bunch of folks claiming 15MPG in an FSJ with a heavy foot and up to 20MPG if light on the pedal. Definitely tempting!

Got a few questions on the 5.3
Looks like there's a couple different versions of the 5.3, one is OHC and one is not. Which one do I want and what year range is the most desirable?

Some GM vehicles with the 5.3 were set up as "Flex Fuel" vehicles. Are all 5.3 engines compatible with E85?

There's several stand alone ECM and wiring kits online. What are the pros and cons of the different kits?

Got a few questions on the tranny and transfer case
Looking to use a 4L60E or 4L80E, what transfer case options do I have? Can I use the stock NP229 or BW1339?

Regardless of what transfer case I use do I have to get rid of the factory fuel tank?

Can I use the stock Jeep steering column or do I need to use a later GM truck column already set up for an overdrive trans?

Last but not least is there a way to keep the "Tow Haul" feature with the stand alone ECM for towing purposes?

Thanks for the help!

[Stuka]

I'm planning out a future GW build and all of this talk about GM 5.3 swaps lately has got my attention. I see a bunch of folks claiming 15MPG in an FSJ with a heavy foot and up to 20MPG if light on the pedal. Definitely tempting!

Got a few questions on the 5.3
Looks like there's a couple different versions of the 5.3, one is OHC and one is not. Which one do I want and what year range is the most desirable?

Some GM vehicles with the 5.3 were set up as "Flex Fuel" vehicles. Are all 5.3 engines compatible with E85?

There's several stand alone ECM and wiring kits online. What are the pros and cons of the different kits?

Got a few questions on the tranny and transfer case
Looking to use a 4L60E or 4L80E, what transfer case options do I have? Can I use the stock NP229 or BW1339?

Regardless of what transfer case I use do I have to get rid of the factory fuel tank?

Can I use the stock Jeep steering column or do I need to use a later GM truck column already set up for an overdrive trans?

Last but not least is there a way to keep the "Tow Haul" feature with the stand alone ECM for towing purposes?

Thanks for the help!

I can't answer all of these, but I can answer some.

1: There has never been an OHC 5.3 GM V8. Or any SBC based engine. They are all pushrod engines. Some do have variable valve timing, but its a fairly poor implementation. But it does help.

2: The FlexFuel bit has more to it than just the engine. There is a sensor that senses the different gas, and changes the ECU (or at least Ford does, not sure on GM), the tank and all the lines are rated to be safe for the high alcohol content. Standard lines don't last.

3: For transmission, the 5.3 never came with a 4L80E. Only the 4L60E. So if you find a combo, this is what it will have. As for T-Case, the 1339 is out (and why would you want it anyway?) There are several NP cases that can easily be connected to them. If you really want AWD, look for an NP242.

4: Factory tank should be fine, as you have an 80+ rig.

5: Most swaps I have seen use a floor shifter.

6: Tow Haul can be kept, and just requires a button to engage and disengage it.

[Grand_Wag_85]

Thanks for the intel Stuka, that really cleared a lot of stuff up.

[Grand_Wag_85]

While searching for 5.3 stuff I came across a bunch of 6.0 swap stuff. Are the outer dimensions of the 5.3 and 6.0 identical? Any benefits of the 6.0 over the 5.3? Only reason I ask is because it looks like you can get a remanufactured 6.0 cheaper than a 5.3 take out.

Never thought I'd say this but the more I look into this the more I'm favoring a Vortec swap over a 401.

[Stuka]

The 5.3 and 6.0 both share external dimensions. They are pretty close to the same basic block design.

The 6.0 certainly has more power, especially if you get into the Vortec MAX and such. But fuel economy may suffer due to it. I know my father has a 6.0 MAX in his '07 Silverado. Tons of power, horrible fuel economy.

[86gwrhino]

just stay away from 99-2000 gen 3 engines. they are still excellent motors but they are cast iron blocks, newer ones were aluminum, and theres a little piston slap in the 6L. my dad's 2000 2500 burb has a 6l with the piston slap issue (it sounds like a deisel) he gets 14mpg highway but thats in a 5800LB truck. and tcase wise try for a np241, they came bolted to 4l60s but if going with a 6L and 4l80 get a np246, its stronger but the case is weaker.
all tow haul does is make the tranny shift higher for pulling heavy loads so all you need is a button as said previously. cant go wrong with either though!

[lindel]

My '03 had a cast iron block 4.8L, and never had an issue with piston slap. Had 233,000+ on it when I traded it in for my TJ.

[Stuka]

As far as I know, trucks didnt switch to aluminum blocks until 07.

[86gwrhino]

As far as I know, trucks didnt switch to aluminum blocks until 07.

my bad i meant aluminum heads, 99-00 still had cast iron heads. only the lq9 had an aluminum block.

My '03 had a cast iron block 4.8L, and never had an issue with piston slap. Had 233,000+ on it when I traded it in for my TJ.

it only realy showed up in the 99-00 model lq4 6.0. the 5.3 had a little not much. the v6s didnt have it at all.

[The PIG Smith]

3: For transmission, the 5.3 never came with a 4L80E. Only the 4L60E. So if you find a combo, this is what it will have.

It is my understanding that 4L60E TCM/ECM will talk to a 4L80E and only needs some sort of flash only to change shift points.
The same ECM works for a 5.3/4L60E as does the 6.0/4L80E

Now, having typed this, I would strongly recommend researching this to N-th degree.
I would feel bad if some dropped some coin on a 5.3 and 4L80E and then would not work.
"Some fat ol' gesser in Indiana told me it'd work"

[j20owner]

I think it'd work. FWIW, until about '06, the TCM is built into the ECM. It's going to need tuned anyways, so I'm sure it can get figured out in the long run.

[bigun]

Am I going to have to turn you over my knee for even contimplating put a generic motor in an FSJ? Dang boy I thought you had more sense. Dude do not let BlackBart hear this or we'll be making a road trip to your house!!!!!

[Grand_Wag_85]

"Some fat ol' gesser in Indiana told me it'd work"

I'll just drive down US30 and slap a brow on the first J truck I find

Am I going to have to turn you over my knee for even contimplating put a generic motor in an FSJ? Dang boy I thought you had more sense. Dude do not let BlackBart hear this or we'll be making a road trip to your house!!!!!

Eh, I was just thinking out loud, I think you know me better than that.

[bigun]

"Some fat ol' gesser in Indiana told me it'd work"

I'll just drive down US30 and slap a brow on the first J truck I find

Am I going to have to turn you over my knee for even contimplating put a generic motor in an FSJ? Dang boy I thought you had more sense. Dude do not let BlackBart hear this or we'll be making a road trip to your house!!!!!

Eh, I was just thinking out loud, I think you know me better than that.

Now the IHC 392 swap Craig might want to help you with that one

[Grand_Wag_85]

392 in an FSJ would be sweet along with a T18.

[CAPTSmith]

As a new forum member, I'm excited about all the engine swap intel that I've seen and hope to see in the future - a very nice FSJ network - THANKS! Has anyone done a Vortec 6.0/4L80e/NP241C swap in a FSJ? My '88 JGW has been great, but needs a reliable GM drive-train, and of course welcome your FSJ/engine swap intel!

[lindel]

First off, Welcome Capt Smith!

If you register over at the Mothership (www.ifsja.org), assuming you haven't already, you'll need to look up an individual that goes by JeepinPete. He was one of the first to do it, and can answer a lot of your questions.

The LS family of engines is one of the easiest to swap, if you have the harness, PCM, and fuse block. Add the transmission and transfer case and it gets easier, especially if you have a later model GW (from 80 to 92).

[CAPTSmith]

Thank you Lindel for the warm welcome and quick reply! Yes, I know Jeepinpete and IFSJA forum. Jeepinpete motor mounts are the best! Your fsj network forum is the best and most responsive I've used - THANKS! Also, can I get access to upload project pictures?

[lindel]

Sounds like you've already got a good handle on it.

As far as pictures go, I use a photobucket account and just link pictures by copying and pasting the img code provided by photobucket. That way you don't use up much bandwidth posting pics, and can share them across different forums, etc. No cost to you for a basic account, and I haven't reached a limit for pictures or bandwidth yet.

[CAPTSmith]

I'm up and running now w/pocket bucket, thanks again!