4.2 L vs. AMC 360 V*???

coronasup

Member
Joined
Sep 18, 2013
Location
Charlotte, NC
Just bought a 76 CJ5 with a good running 4.2L but have a 360 V8 for it. Anyone have an opinion on which to use? Will be used off-road some but mostly beach hopper. Thanks!
 
I'd go with the 360. I've had both and loved the 360.

But, you'd need a new radiator and likely a better transmission to hold up to the V8. With it being a 76, its likely you have the T150 trans? You'd want to upgrade to the T18 or even a T176 to hold up to the 360.
 
they both weigh about the same - i'd go for the 360 too.
the torque difference is great when wheelin and on the street.
 
I would like to put that old 4.2 in my 90' with the 2.5.

:bounce: if you wanna sell it let me know.
 
rockcity said:
I'd go with the 360. I've had both and loved the 360.

But, you'd need a new radiator and likely a better transmission to hold up to the V8. With it being a 76, its likely you have the T150 trans? You'd want to upgrade to the T18 or even a T176 to hold up to the 360.
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Pretty sure the radiator is the same. As long as it's a three flu. All the six cylinders I've had already had three flu rad.

Changing the engine out is strickly your preference in just a beach hopper. They both will get the job done but the 360 sounds alot better.
 
I would go 360,in my exp. you dont need to change the radiator and if you are easy on the t150 it will hold up fine, 304 w/ t150 was a factory setup in many cj-5 . 258 is a great motor and loads of torque but run out of power at about 4000 rpm. AMC V-8's are a very underrated motor and can be built as nasty as you want. You will need to have a exhaust run for the 360.
 
Thanks for all the advise. Nash, I have all or most of the components to build the 360 just need someone to do it. Know anyone in the Charlotte area? If Bogleparsons wanted to barter and build the 360 I would give him the 4.2L. Thanks!
 
If you decide that T150 isnt strong enough, I have an SM420/Dana300 combo that works great in a CJ-5.
 
coronasup said:
Thanks for all the advise. Nash, I have all or most of the components to build the 360 just need someone to do it. Know anyone in the Charlotte area? If Bogleparsons wanted to barter and build the 360 I would give him the 4.2L. Thanks!
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I wish I could but internal motor work is about the only thing I havn't done before.

I'll PM you about the 4.2 once I talk to the wife haha
 
coronasup said:
Thanks for all the advise. Nash, I have all or most of the components to build the 360 just need someone to do it. Know anyone in the Charlotte area? If Bogleparsons wanted to barter and build the 360 I would give him the 4.2L. Thanks!
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I havent had a motor built in a while, I would ask around on here but machine shops dont charge alot for assembly of the long block then its cake. Im sure someone on here can and will do it. Post in the vendor/shop section for reply. good luck
 
The 360 is the cheapest to rebuild of the amc motors. Bluecj rebuilt a 258 and 360 at the same time. Even with the extra money for machine work it was about 100 less than a 258. The t150 should be fine for what youre doing. Another thing no one mentioned is gas milage. Surprisingly you should only be down 1 -2 mpg by upgrading to the 360. You will need a pass. side frame mount to do the v8 switch. Also if you do decide to switch trannies, A t18 from a 258 j10 is only about 3/4 of an inch longer than the cj version and much easier to find. Good luck.
 
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