Input needed: Fuel inject stock 258 or 5.3L swap

Super 8

Legacy Registered User
City
Bozeman
State
MT
#1
A little background. I bought a CJ8 earlier this year. It is a nicely optioned Laredo model. It has a rebuilt engine and transmission. The engine runs rough. I am on the fence what to do with the drivetrain. Do I keep it relatively stock or swap in a late model 5.3L and 4L60E? I know how good the GM parts are, I have done many swaps. I would like to hear feedback from folks that have used off the shelf fuel injection kits (Howell, Holley, Mopar). Thank you!
 

HighSierra CJ

Scrambler Enthusiast
LIFETIME
CJ-8.com Member
City
Ducor
State
Ca
#4
I’d keep the stock motor. Just my opinion/preference. I have two Scrambler’s with the Mopar fuel injection, And another Scrambler with the Howell fuel injection. They all run great.
 

sdsupilot

CJ-8 Member
CJ-8.com Member
City
OKC
State
OK
#5
I think it depends on your expected use and what power level you want to have. Passing power, burnouts and up hill acceleration favor the v8 over i6. I have a 4.3 v6 in my Scrambler. The only place I would prefer more power would be 65 mph highway cruising.
 

Super 8

Legacy Registered User
City
Bozeman
State
MT
#6
Recommend getting the 258 running correctly first.
The carb is bad. So I would have to rebuild or replace it. I rather not throw more money at the carb.
If you put in the V8 you will need to upgrade the entire drivetrain. Just FI the 6 cyl.
Yep. I've done a few dozen V8 swaps. I would use a GM auto transmission and a set of Dana 44 axles I already have.
I think it depends on your expected use and what power level you want to have. Passing power, burnouts and up hill acceleration favor the v8 over i6. I have a 4.3 v6 in my Scrambler. The only place I would prefer more power would be 65 mph highway cruising.
I'm older, so power isn't my motivation. Reliability and drivability are what I am going for. I have a LJ that is my offroad jeep. The CJ8 is more for fun around town and mild trails.
 

ag4ever

Average Nut
LIFETIME
CJ-8.com Member
City
Richmond
State
TX
#9
Hope to have the sniper efi for the BBD carb installed in a couple weeks on my ‘83. My ‘82 is getting an LS.

So, I suggest doing both.

I plan on making an install thread for the sniper once it arrives. (Should be here this weekend.)

Here is a sneak peak at one of the parts being used.

99DC0275-360C-4778-B101-E454EF86B5F4.jpeg
 

Scramblin Man

Beyond help
LIFETIME
CJ-8.com Member
City
Woodway
State
Tx
#10
I’ve never done a V-8 swap, but would say 258 with EFI from your use description. I have one with Mopar EFI and it has plenty of power for me. Plan on putting either Howell or Holley EFI on another 258 Scrambler this summer. Would do the Mopar if Hesco had complete kits.
 
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Belizeit

CJ-8 Member
CJ-8.com Member
City
River Ridge
State
La
#11
image.jpeg image.jpeg
Hope to have the sniper efi for the BBD carb installed in a couple weeks on my ‘83. My ‘82 is getting an LS.

So, I suggest doing both.

I plan on making an install thread for the sniper once it arrives. (Should be here this weekend.)

Here is a sneak peak at one of the parts being used.

View attachment 83343
I'm wondering why you elected not to go with the sniper in tank pump for the BBD replacement ?
 

Domin8

Scrambler Enthusiast
LIFETIME
CJ-8.com Member
City
Astoria
State
NY
#12
I’ve never done a V-8 swap, but would say 258 with EFI from your use description. I have one with Mopar EFI and it has plenty of power for me. Plan on putting either Howell or Holley EFI on another 258 Scrambler this summer. Would do the Mopar if Hesco had complete kits.
I have no first hand experience with this, but Hesco just released a new "Gen 3" MPFI system.

This is what I am strongly leaning towards using on mine...whenever I get there. Maybe if I wait long enough, I'll do a "Gen 4!" :cry:
 

Scramblin Man

Beyond help
LIFETIME
CJ-8.com Member
City
Woodway
State
Tx
#13
I looked over their website recently and the kit they now offer looked different than the Mopar. To me looked like a repackaged/customized sniper EFI. I talked with them about a year ago, the problem with the Mopar kit was non-avability of the proper computer and the discontinuation of some of the connectors for the wiring.
The new kit may be better than their prior Mopar kit, hopefully so.
 

Domin8

Scrambler Enthusiast
LIFETIME
CJ-8.com Member
City
Astoria
State
NY
#14
I looked over their website recently and the kit they now offer looked different than the Mopar. To me looked like a repackaged/customized sniper EFI. I talked with them about a year ago, the problem with the Mopar kit was non-avability of the proper computer and the discontinuation of some of the connectors for the wiring.
The new kit may be better than their prior Mopar kit, hopefully so.
Supposedly, their new system is supposed to be 50 State/Carb legal.

Due to where I live, that is necessary for me.
 

ag4ever

Average Nut
LIFETIME
CJ-8.com Member
City
Richmond
State
TX
#15
I'm wondering why you elected not to go with the sniper in tank pump for the BBD replacement ?
20 gallon poly tank vs 15 gallon steel tank. The Holley drop in is for the steel tank. I don’t think they have one for the poly tank.

Either way, this keeps all new wiring under hood. Also, my boat has used a similar “fuel control cell” as pleasure craft marine calls it. Has worked great for 18 years. Figured if it was good enough for a boat, should work well on a Jeep. Also keeps me from dealing with an “out of tank” fuel pump.
 

MomoJeep

Basic User
CJ-8.com Member
City
Seattle
State
WA
#16
I have the MPI from years ago and it runs great after working out a few bugs. Yeah, they stopped making the specific computer, but the 4.0L computer works with one or two tweaks to keep the engine light off. It runs really well and reliably. I don't need more power unless I wanted to drive 70mph (which was never part of the original design!) or break stuff.
 

Randyzzz

Blown Budget
LIFETIME
CJ-8.com Member
SOA Member
City
Redmond
State
OR
#17
This might sound strange for coming from the guy that puts an LS in everything- but if it is really a nice Laredo, and you aren’t power hungry, keep the 258 and do the EFI conversion. Original is always highly desired, and there is something indescribably cool about cruising a stock Jeep.
 

Super 8

Legacy Registered User
City
Bozeman
State
MT
#18
This might sound strange for coming from the guy that puts an LS in everything- but if it is really a nice Laredo, and you aren’t power hungry, keep the 258 and do the EFI conversion. Original is always highly desired, and there is something indescribably cool about cruising a stock Jeep.
I agree Randy. This is the first CJ8 that I have had that was bought as a complete jeep. It was much easier in the past to put a LS or 4BT in a jeep that started off as a pile of parts. I am leaning towards the Holley kit.
 
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