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Old 08-20-2011, 07:11 PM   #1
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I need yj engine swap info plz

ok. so i have a 94 yj with a 2.5litre in it. but my buddy just gave me a late 70's running 304 from a cj. i wanna do the old motor swap and get rid of the crappy 4 cylinder, but i wanna do some heavy planning before i start ripping things apart. can anyone tell me what all i need to know before doing this? i found motor mounts on the internet for 150 from novak conversions, but thats as far as i have gotten. what do i do about the wiring harness? fuel pump (since im going from injected to carburated), and im trying to do this with as small of a budget as possible.

thanks guys
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Old 08-20-2011, 07:47 PM   #2
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You will need a trans and transfer case, axles, and whole lot of fabrication....

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Old 08-20-2011, 08:29 PM   #3

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I can get you started. With *lowest* cost in mind....

1. You can eliminate the electric fuel pump and go with tha mechanical set up.
2. You will need a transmission and transfer case that handle the motor and start looking for a stronger rear axle too.
3. The cooling system will need to be upgraded and you will most likely need a radiator and electric fan.
4. The alternator may need to be upgraded if you run anything other than the fan.
5. The ignition system can be simplified by running an HEI rather than the stock distributor ignition set up.
6. You will need a complete exhaust system.
7. If you run a TF999 or RH32 auto transmission it can handle a stock 304.
8. If you are changing the type (auto or manual) you will need the shifter and pedal set up for the tranny you choose and kickdown cables.
9. Proper flexplate for the tranny.
10. If your jeep is not lifted and has the original spring the front may end up a little low.
11. After you buy those motor mounts, weld in the mounting pads to the frame and throw the engine mounts in the trash. They won't last. Buy a heavy duty set like the MORE Bomb Proof Motor Mounts.

That should get you started.
You would probably be better off to sell your four jeep and find a 88 or 89 with the 258 and automatic tranny. Just pull the motor and start from there.
Good luck.
Nothing is foolproof to a sufficiently talented fool.
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Old 08-20-2011, 10:35 PM   #4
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By chance, are you in a state that does emissions testing?
If so, you will never get that past the smog Nazis.....

if not, well, some day you might have a BIG headache when your state adopts emissions testing.

My question is why did your friend pull the 3.4? I would save it for a CJ project later in life, or Craigslist it for money to put towards a proper engine swap.

If you are dead set on using the 304, check out Advanced Adaptors and Novak for transmission and transfer case adapter information.
Wiring will be an issue too, get a complete diagram for your current setup and listen to Fweaky too!
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Old 08-20-2011, 11:19 PM   #5
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Fweaky thanks that helps a lot. It has a 5spd in it right now and I refuse to own an auto so I'm gonna throw another stick in it. My buddy has a 4 sod.Chevy tranny he thinks will work so were gonna try to go that route. It's listed on novak as one of the ones that will bolt up. Then ill just have to find a transfer case. It's def gonna take some work but u can't beat a free motor and I love my yj so Imma put in the time and effort and make it sweet lol. 2xs my county doesn't have emmissions yet so ill worry about it when the time comes. Lol thanks for the help guys. I appreciate it. I'll throw pics up when I start making progress
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Old 08-21-2011, 12:48 AM   #6
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Hey fweaky what do I do about the electrical system

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304 , motor , swap

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