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Discussion Starter · #1 ·
I have a 82 cj-7 with a 258, T-5 tranny, and Model 300 transfer case. I am thinking about swapping in a v8. First of all, would it be better to go with the AMC 304 or the Chevy 350? And second, which will be the easiest, cheapest, etc? What kind of adaptors would I have to buy and how much should I expect the total project to run me? Thanks

 
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The first thing is I no nothing about any of this.
The thought has passed my mind that a guy could go to the
chevy. motor and a 4500 trans then you only have to buy the adap.
for the 300 tranfer case. or
sb-4500-205 tranfer case??? I don't know which side the 205
front axle drop is on????
I think I would try to stay with the 300 T.C. .

 

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I think that a 304 will bolt right up to the transmission. This will save you buying an adapter. I'm not sure but I think that your current tranny and transfer are pretty good equipment so I'd stick with these.

87 wrangler

 
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I am a HUGE fan of the CHEVY 350 conversion. You can buy a rebuild kit for $160 complete. I have about $700 into my brand new chevy engine that puts out about 280 hp. Then you can go to a yard and pick up a tranny and t case for next to nothy. I currently have a th400 with an np205 transfer case.(passenger side drop) I probably don't have more than a total of $1500 into the entire conversion....plus I still ahve my old dana 300 and 999 tranny to sell. Another wise upgrade is a larger radiator and electric fan. You can use stock mounts from an older monty carlo for engine mounts, because they are metal and you can weld "spacers" to raise the mounts and bolt into your frame instead of welding. If you can do most of the work yourself....go for it...its cheap and chevy parts are the CHEAPEST out there...cheqp to upgrade/repair and plentiful in yards and parts stores. If your paying someone to do it, I would be apt to look into the amc v-8 a little more. It just comes down to what you can get for what price.

my .02

~~TIM~~

I'm not afraid of dying...I'm scared of not living

chevy-Cj-7
 

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i would not put a 304 into a cj.. i would just bolt a 360 right in..bolts to the tranny(t-5) and the dana 300 is a great x-fer case..i did about 4 of these now, and it only takes 1 good day..
the only thing you have to find is a pilot bushing..they are different for the t-5 than with any v-8 application.. i used one from a ford that matched the inner diameter and ground it down to fit into my 360 block by doing the following...
1..buy a couple at the local parts joint(i think ford 302 bearing)
2..put a bolt through the center and cinch a washer and nut on the botton,,make sure the bolt hangs out the bottom a couple inches
3...put the bolt right into the chuck of a drill, cinch it down, put the dril in a vice, and hit the bushing with a file until it fits into the block...
this whol process took me only about a half hour(the other bushing is in case you screw up the first one).
i have had both chevy and jeep powered jeeps, the amc engines are the most bang for the buck...if you don't want 500 horse


~~Elusive~~
it's sort of still a cj thingy....
 

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I have a small block chevy in my 80 CJ5. Check with http://www.mountainoffroad.com/catalog/BombProof MM/bombproof.htm for information about bolt in small block chevy motor mounts for a CJ! I've got the Mountain Off Road motor mounts in my CJ5.

If your budget is limited, the 304 would be less expensive. The 304 is more expensive to rebuild than a chevy small block. The best advantage of the 304/360/401 is no adapter will be required. Most all the parts you need for the AMC V8 option could be purchased used.
dave
 

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Discussion Starter · #7 ·
So the 360 and the 304 should just bolt right in if I can find one in good shape that doesn't need a rebuild? Another factor is gas mileage. How bad is the miles per gallon on the 360 and 304 compared to the chevy 350? Thanks..

 

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http://www.off-road.com/jeep/tech/engine/amc258.html

Look at this web-page for Jeep engine data. The difference in power from a 258 to a 304 is not that great. Actually, going to a 360 makes more sense as far as bang / buck ratio. Going to a Chevy will cost more. I don't really know anything about Chevy power vs. AMC power.

Loose nut behind the wheel
Another right-wing conservative.....
Born and raised in Jeep-Town
 
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The stock six pilot bearing will fit the AMC V-8s perfectly, as the crank flange is the same '72 and up. The 304 will be ok with the t-5, but a 350 or 360 AMC will break it quickly unless you baby it. The AMC conversion requires a new right side frame bracket and special CJ only engine block brackets that are still available new from the dealer, for around $120, or used at a wrecker. The stock 6 radiator will work ok if it is a 3 row/AC type. The V8 fan shroud is still available new and is recommended. A 2 row would probably be OK in the northern areas though. A chevy conversion requires the hose outlets to be switched to the opposite sides, easily done by any good radiator shop. Expect around 12-13mpg if the V8 is close to stock. The AMC swap is very easy, and the result looks and acts like the factory did it! The Chevy is more work, but the parts are cheaper. In either case, be sure to get all of the accessories with the engine, as buying all the brackets, bolts and fittings adds up very quickly. Hope this helps, good luck!







 
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What about tossing in a an AMC 401 vs the 360. I know where I can get one, I just want to know if it's worth it. tia

Steve
/wwwthreads_images/icons/crazy.gifJust Empty Every Pocket/wwwthreads_images/icons/crazy.gif
 

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401 is the same deal..except it is harder to keep cool..real attention must be paid to the cooling system, but it still bolts right in....but i don't know how you get that little pilot bearing from the 258/t-5 combo to work in the amc v-8...at least not if the t-5 was oem



~~Elusive~~
it's sort of still a cj thingy....
 
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Go for the 401. That's what I'm looking to do and I have a freshly rebuilt 304 now. In my experience the only problem I'v had with the amc v-8 is that with all too few miles on them they strat to smoke upon startup, I don't know if it an inherant flaw in them or I'f i'm just to hard on them.

Al
My web page
 
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