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looking at this engine...

wimps81096

wimps81096

CJ-8 Member
City
white lake
State
MI
it was recommended to me that i look at Jegs for a possible new engine for my rebuild. Does anyone have any experience with this engine? What modifications would be necessary to fit with the A999 auto trans and dana 300 that i would like to reuse? I dont want to go crazy, HP wise, but want it all to work together.

Are there other crate engines you would recommend and where would i find them? I was advised to look for a chevy LS 350 but cant find one available and, as a turn key option, was much more expensive.

Any thoughts?

https://www.jegs.com/webapp/wcs/sto...&submodel=&engine=&Nrpp=&No=&persistYmm=false
 
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Probably a fine engine- Jegs has always treated me fairly.

At this price you should be able to find an LS1 motor. My local Craigslist has 3 in the immediate area. I looked in Detroit- seems to be a couple of good candidates (and harnesses) in the auto parts section. Just inspect it real well.
Best of luck.
 
Advance Adapters has what u need to bolt up your transmission to that fine engine
 
What is your plans for your Jeep? Check the torque curve on the engine. If it makes power up high in the RPM band, you could probably find a more suitable engine to swap in.
 
barrys said:
What is your plans for your Jeep? Check the torque curve on the engine. If it makes power up high in the RPM band, you could probably find a more suitable engine to swap in.
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I tend to agree with this, do you get a choice of cam profile? Also I wonder if at 375 HP these motors have four bolt mains? It seems like an awful lot of ponies for a Jeep!
 
No input on the motor as I'm not a Chevy/V8 guy but it's nice to see this discussion from you :popcorn:
 
bigwalton said:
No input on the motor as I'm not a Chevy/V8 guy but it's nice to see this discussion from you :popcorn:
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to quote eddie murphy, "thanks, you been he'pful." Of course the other option is to rebuild the 4.2. Its not out of the question, yet. There seems to be nothing wrong with it. Also, I assume from your "nice to see this discussion from you" that you didn't think I'd get this far?
 
barrys said:
What is your plans for your Jeep? Check the torque curve on the engine. If it makes power up high in the RPM band, you could probably find a more suitable engine to swap in.
Click to expand...

My only plans are to have a good running reliable jeep. Im not a speed or horse power guy by any means, Just want to have enough power to have fun with but not go overboard. I also know nothing about engines so if you have recommendations for a "more suitable engine to swap" I am definately open to them.
 
Not at all, just that I’m glad you’re to the point where you have to get this sorted.

I’m all about fuel injection now. I liked the nostalgic side of having a carb on Mater but swapping on the FAST throttle body kit has ruined me for ever messing with carbs again. So my comment, since you’re really just looking for reliability and a solid driver is to plan for FI as a part of this swap, whatever that looks like.

Certainly nothing wrong with a crate 350 if you’re able to keep out of the gas for the sake of saving the driveshafts and axles. You’ll certainly enjoy it at the dunes ;)
 
bigwalton said:
Not at all, just that I’m glad you’re to the point where you have to get this sorted.

I’m all about fuel injection now. I liked the nostalgic side of having a carb on Mater but swapping on the FAST throttle body kit has ruined me for ever messing with carbs again. So my comment, since you’re really just looking for reliability and a solid driver is to plan for FI as a part of this swap, whatever that looks like.

Certainly nothing wrong with a crate 350 if you’re able to keep out of the gas for the sake of saving the driveshafts and axles. You’ll certainly enjoy it at the dunes ;)
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Sounds like a good time for a LS swap.... Just sayin'.....
 
My last Jeep came with a tired, high mileage, but good running 258.

I wanted a little more "oompf," so I installed a rebuilt 258, and MOPAR MPI fuel injection (basically 4.0 HO fuel injection), and Borla exhaust. It ran smoother, and had better throttle response... but it didn't quite give me the performance I was expecting....

Then I added a 4.0 HO cylinder head, and WOW, that engine came alive! It probably had the horsepower of a basic Chevy 350 or Jeep 4.0 HO (200-ish), but it retained the low end torque of the 258. I could roll around a slow corner in second gear, at maybe 600 rpm, and when I gave it the gas, it pulled out like a diesel!

If I wanted to freshen up a Jeep with a 258, I'd rebuild the engine, with a 4.0 HO head and fuel injection (multi point would be preferable, but TBI would work nicely as well), and never look back.

Also, a full 4.0 HO swap would be a valid option, and would be compatible with your 999 transmission.
Good luck! :cheers:
 
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I agree. If it is swap time might as well go FI and at that point you why not LS . Or diesel:unsure::unsure:
 
CJ7Pilot said:
My last Jeep came with a tired, high mileage, but good running 258.

I wanted a little more "oompf," so I installed a rebuilt 258, and MOPAR MPI fuel injection (basically 4.0 HO fuel injection), and Borla exhaust. It ran smoother, and had better throttle response... but it didn't quite give me the performance I was expecting....

Then I added a 4.0 HO cylinder head, and WOW, that engine came alive! It probably had the horsepower of a basic Chevy 350 or Jeep 4.0 HO (200-ish), but it retained the low end torque of the 258. I could roll around a slow corner in second gear, at maybe 600 rpm, and when I gave it the gas, it pulled out like a diesel!

If I wanted to freshen up a Jeep with a 258, I'd rebuild the engine, with a 4.0 HO head and fuel injection (multi point would be preferable, but TBI would work nicely as well), and never look back.

Also, a full 4.0 HO swap would be a valid option, and would be compatible with your 999 transmission.
Good luck! :cheers:
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sounds like a valid option if i choose to forgo an LS or similar swap. Might have a few more questions for you if you are willing and available.....
 
wimps81096 said:
sounds like a valid option if i choose to forgo an LS or similar swap. Might have a few more questions for you if you are willing and available.....
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Sure, I'd be happy to help! :thumbsup:
 
That engine is is better suited for a lighter weight car like a Camaro. I have used that cam in many engines I've built. Peak torque will be around 4500 and peak hours above 5500.
 
Click on the link and then details, then overview. It's 224/230 duration at .05 with a 110LSA .480 lift. Obviously you couldn't run more lift because of the vortec heads but I am surprised it doesn't have a bit more compression. You can easily run 10:0 on pump gas with that cam.
 
mysunnshine said:
Yea but not with those iron heads.....
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Why? Its a very common setup. My friend down in Dallas had that same setup with vortec heads and 10:0 comp in his 85 Camaro that he daily drove for years without a single issue. Vortec heads do pretty good for a guy on a budget that wants a healthy 350-400 hp motor. But I think there is a better choice for a Jeep than this engine.

Wimps81096 The LS 5.7L was the aluminum engine in the Firebirds/Camaros. Those usually go for a lot more money. If you're looking at LS engines check out either the 4.8 or the 5.3 found in Chevy trucks and suburbans from 01 to 06. They are cheap and plentiful. I bought mine used with all the accessories, starter, harness, and computer with 86,000 miles for $500. These engines easily go 300,000 miles if you take care of them.

If you really want to stay carbureted then do your search for an 87 up Chevy 350. These had the nice one peice rear main seal as opposed to the leaky 2 peice seal in the pre 86 motors. Ever notice how like every other Jeep on the road leak oil from the back of the motor? AMC used 2 peice seals in their engines.
 
I have learned on the dyno that the control for power is now the fuel(pump). The days of high compression traditional engines is gone. With the pump fuel we have now, you can make the same amount of power with a lower compression and more timing than a higher compression motor with "normal" timing. Compression is not your friend anymore. Granted, the LS motors now are running some pretty high numbers now but there are other design reasons why they can do that. The biggest reason is the aluminum heads and the chamber design. For a street motor, I would not go past 9.25 myself and that's with AL heads. Another issue with compression is that it makes heat and a louder exhaust tone. Heating issues are a super common issue in CJ's already so why push the envelope and have to over-design everything to work with that high compression?
 
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