4 banger to v8 smart idea or no?

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blue94yj

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Jeep Wrangler (YJ) Upper half doors (for stock soft tops)

I have a 94 yj with a 4 banger and its stick. It sits on new 31x10.5 and i notice a big difference from the smaller ones it had when i bought it. The 4 cylinder has just under 123,000 miles on it but on the transmission 3rd and 4th gear the syncro rings are broke so i have to shift real slow so it dont grind and even then it does it. I was running thoughts threw my mind today and am thinking about droping a new chevy 350 motor in it with a new manual transmission. My question is, do u guys think it is worth it to swap to a 350 for the power and no mileage but with gas prices rising around here to just under 2 bucks, plus i dont know how much work or how hard it is to do this. Or should I just buy a new straight 6 4.0 and get a nice used but rebuilt transmission for that. Still deciding but i wanna go bigger and the 4 cylinder just isnt gonna do it when im just that big.
 

I'd say if you have a little time and a little money, put the 350 in. You will be so much happier than the crappy 4 cyl. It is worth it. Parts are always available at any auto store for the chevy 350. I am in the middle of my swap now.
 
I would say to go for it, if you have the time like bryanjeep said. The gas mileage really isn't all that bad on all the 350's (depending on year, etc). I'm not sure about your 4 cyl, but mine gets terrible gas mileage, and it's completely stock. Also, if you plan to do the work yourself, or most of it, it really doesn't cost all that much.
 
I was running thoughts threw my mind today and am thinking about droping a new chevy 350 motor in it with a new manual transmission.
Click to expand...


Do you mean a new AX-5 or a GM transmission? A new AX-5 is a waste of money, and an even bigger waste behind a V8.
 

Thanx for the input. My 4 banger with the 31's gets just about 250 miles to tank if i shift at 2 grand all gears otherwise i get about 175 miles to tank driveing it how it should be droven. Also The motor and transmission is out of a 57 chevy that my dad said i can have. Motor has no more than 2000 miles on it so im guessin it should be all good.
 

no... you can get a good intake and a fuel efficient carb... but if that motor is old and tired... the cam may cause you to lose some power, keeping your foot on the floor a lot... i would think that a 57 would need a few bucks put into it before it would be a good gas saver
 
Don't waste your time installing a 4.0L, it's the same expense and labor, or more, than installing a GM v8. And you'll have a rougher looking install than a factory 4.0L and you'll be just like all the other 4.0L jeepers out there. Do something different.

Install a GM 4.3L Vortec v6, can easily be found in Chevy and GMC s10 pickups and blazers, and in full size 1500's. Common with the 5speed and the NP231C or NP241C transfer case.

It's an awesome engine, lighter than the 350 and easier to install. Better mileage and can make some awesome power. I've installed a 350 into my old YJ, and I'd do the 4.3L if I ever do another engine swap.
 
i'd definitely go with a 4.3 if availible... they are often mistaken as a v8 when nobody can see under the hood.. their power is quite impressive... and, they sound nice too
 

i can get a v6 rs camaro motor for pretty cheap like prolly 100 bux but its automatic idk if itll line up with my transmission or not.
 
i'd honestly rather have a 4.3V than a v8... much better gas... less common... just as good of power
 

4.3L v6 can make as much power as a stock 350, easily and inexpensively. They are commonly found with autos and manuals, so choice is there. Real common in the junkyards too, so many are wrecked and still have good drivetrains.

I've swapped a 350 into a YJ, it went pretty well. The 4.3L would be much better suited to a SWB jeep.
 

if you are going from a 4cyl... the stroker really wouldn't be an option i would go for.. unless you were dead set on keeping it Jeep... otherwise, the work and money involved in building and fitting a stroker would by far outweigh that of any other common powertrain
 
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You might as well throw a V8 in it. A 4.3 will be as much work and money, and when done you will be waaaaaay down on power compared to the small block V8.
They are basically the same engine.....with the 4.3 having the front two cylinders lopped off. It will always have to work harder to make as much power as it's big brother, and the parts availability to make that power isn't as good as it is for the SBC. The only advantage is weight, and it isn't THAT big of an advantage in this case.
Sure a fuel injected Vortec 4.3l will make as much power as some of the weaker V8s, but when both engines are configured with similar valve timing and flow characteristics the SBC will outpower the 4.3 from one end of the spectrum to the other. Either engine could be fun, but with the swap being almost identical for both engines, the V8 is the better choice in my opinion.
 
don't go with a v8....take it from someone who has done it. Way too much torque for these little guys. I'm taking mine out and going with the 4.3 vortec. unless you plan on working your way throught the entire drivetrain to beef up the weak points you're wasting your time. I ended up putting in a t176 transmission, model 20 case, and had to convert to chevy axles. Within 5 months of driving it i broke two rear leaf springs. PLus the weight of that motor screws with your handling. If i were you i would stick to the 4.0....It's great to be unique and do something different, but the only outcome is you're the one fixing it every weekend while your friends are up the mountain. Sorry to burst your bubble...just thought i'd share my concern....good luck with your swap.
 

really like mentioned before, putting all that money into a 4.0 really wouldn't be worth it or even a 4.3. But hey, good luck on whatever you decide.
 
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