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350 or a 340

J

JeepCherokee25

NAXJA Forum User
Location
Canada
I have a 1990 Jeep Cherokee 4.0L with the aw4 tranny. I am going to either put a 340 or a 350. I need a new transmission because the aw4 i don't think will take 200 more horsepower. What do you suggest for a set up so i don't have to change the driveline?
 
JeepCherokee25 said:
I have a 1990 Jeep Cherokee 4.0L with the aw4 tranny. I am going to either put a 340 or a 350. I need a new transmission because the aw4 i don't think will take 200 more horsepower. What do you suggest for a set up so i don't have to change the driveline?
Click to expand...

I don;t think either one will make 400HP without some heavy work. It would be far cheaper to build a 350 as the 340s were only "good" for 3 years(steel crank and good heads) 68-71
 
I dunno about 450 horses, but the AW4 is pretty durable and reliable if kept cool. (a version of the AW4 was used behind turbo I6 in the 3xx HP Toyota Supra)

Mating that tranny to a chevy or other domestic engine may be cost-prohibitive. - you mention not wanting to change the 'driveline'... the new motor will more than likely shift the crossmember location to some extent, and do you want to keep the 231 or 242 and stock drive shafts behind a V8?- I'd think about using a counterpart tranny/ transfer case to the engine you swap. Do you 'need' an overdrive gear?

If it were me spending, I'd look at strokering or just doing a solid overhaul on the 4.0... but it depends on your goals.
 
My .02 is if you plan on a mopar engine and have a 340 you would be better off selling it and getting a later 5.9 for the xj.
 
Actually the 340 is a better motor than the 5.9l when it comes to overall performance, I'd see if there is a way to adapt the AW4 to a SBMopar and just build that to put behind it. The Shivvie motor is just too cookie cutter to me anyway.........................
 
Novak doesn't make an adapter from any engine to the AW4. If you are swapping in a 350 and want to keep an automatic, the TH350 (non overdrive) or the 700R4 (with overdrive) should be extremely easy to find (and mate) behind a 350. You can get an adapter (again, from Novak, possibly others) from a either of those transmissions to an NP231 or a 242.
 
if i were looking at a V8 swap i'd throw the $$ at the 340. it's smaller, lighter, and revs faster. the latter not really being a concern unless you are gonna race the XJ, at which point i'd tell you save your $$ anyways. the automatic in the TJs was a torqueflite 999, at least for the first few years. THAT will bolt up to the 340, and match it with a 231 and you are on your way. i dont think the TJ trans/t case are longer than the AW4/231 since it comes from a much shorter wheelbase rig.

have you been realistic with yourself about everything else that comes with a V8 swap? exhaust, fuel, electrical, uni-body strengthening??

food for thought... are you prepared for a $10K engine swap into a used Jeep? it adds up fast!!

a nice stroker might be a better choice.
 
For wheeling a 360 is a better build, and plentiful at that. Like I said earlier the GOOD 340s with steel cranks and good X and J heads were only made for 3 years and they were rare then. If you were building a race car I would say 340..but for wheeling :D 360.
 
sidriptide said:
if i were looking at a V8 swap i'd throw the $$ at the 340. it's smaller, lighter, and revs faster. the latter not really being a concern unless you are gonna race the XJ, at which point i'd tell you save your $$ anyways. the automatic in the TJs was a torqueflite 999, at least for the first few years. THAT will bolt up to the 340, and match it with a 231 and you are on your way. i dont think the TJ trans/t case are longer than the AW4/231 since it comes from a much shorter wheelbase rig.

have you been realistic with yourself about everything else that comes with a V8 swap? exhaust, fuel, electrical, uni-body strengthening??

food for thought... are you prepared for a $10K engine swap into a used Jeep? it adds up fast!!

a nice stroker might be a better choice.
Click to expand...
i have said it before and i will say it again, the SBC 350 swap was actually very cheap, shal i list the prices??

  1. 85 loredo with a bad V6 $ 400.00
  2. SBC 350 out of boat $ 0.00
  3. AA bell housing $ 397.00
  4. baisic lift required for the SBC $ 295.00
  5. frame stiffening $ free, i did it
  6. misselaneous items for the engine $ 200.00
  7. fan to keep it cool $ 20.00
  8. trailer to tow it $ 200.00
  9. the look on a know it alls face to see this roll up for under $ 2000.00
05_15_06_1738.jpg


priceless!!
 
bjoehandley said:
Actually the 340 is a better motor than the 5.9l when it comes to overall performance.
Click to expand...

Depends on what type of performance he wants. Nothing wrong with a 340 but the 5.9 would be a better choice in an XJ. 360 cid, longer stroke crank, roller cam, and the 5.9 has better heads.....
 
For a cheap and reliable V-8 swap you can't beat the Chevy 350-TH350. A little off-topic now. I am in the process of installing a 1970 Pontiac 400 dyno'd at 400HP@3800 RPM and 520LbFt at 2100RPM.
 
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