401 in 75 cj5

i recently bought a 75cj5 with a bad 258. 3 sp 4.27 gears. my question is will the stock drive line hold up to a stock 401.or would i be better off just rebuilding the 258. i can get a 76 cherokee with a running 401 th400 for $200

 

forgot to mention the jeep will mainly be used as a hunting vehicle in pa. no rock crawling.. mostly snowy muddy logging trails thamks

 

the TH400 is a long tranny for a 5. You may have issues with the rear ds angle.

The 75 should have a 30 spline Dana 44 NarrowTrack semi floating rear. Which is fine for the power a stock 401 will be making.

My preference would be to rebuild the 258. Lots of low end torque and the Jeep is already set up for it. I don't know which is heavier. the 401 or the 258.

Quick list of things to consider if you decide to swap in the 401.
Exhaust redone
drive shafts will have to be modified (unless you get real lucky)
engine mounts
rewiring engine bay for 401

 

I think a 401 would be really squirrly in a short wheel based Jeep like that. Mileage would not be very good either, but to get through the mud and whatnot, you do need power. You would probably end up breaking a bunch of driveline parts. But, if you upgrade as you break stuff sooner or later you should have a bullet proof drivetrain.

I would really like to find a deal like that around here, maybe in a 304 or 360 though.

Good luck, the price does seem right,
I'm riding the fence on this one

High5

 

Just a thought, but a running 401 for $200? Buy it, decide later what to do. I think you'd maybe make a buck or two on that deal to put towards another 258/304/360 or whatever you decide. Or stick the 401 in. Sounds like a win-win situation to me

 

junker i sent you a pm

 

Junker, what part of PA are you from?

 

thanks for the quick responses. i know the th400 is longer plus id need an adapter since its off a quadratrac, so not really interested in it. i too am partial to the 258 my cj7 has one and have no problems with it. i bought the 75 mainly for the 44 rear to swap into my 78 5.am thinking about restoring it( the 75 ) but really haven't made up my mind. was just wondering what everyone thought of the swap. the 78 is already done and since its a 304 would be a easy swap just dont know yet
plunkinberry i live up around clarion
thanks

 

I agree that $200 for a running 401 is a good deal. Go over to IFSJA and triple your money with the FSJ crowd.

The swap isn't overly difficult but your 3-speed tranny probably isn't up to the extra torque of the big 401 beast. Realistically, an unrebuilt 76 401 isn't going to be a monster but it will have close to double the HP and torque of your 258. There is really no good way to get the TH400 to work in a CJ5. Besides being really long, it most likely had a BW1339 Quadratrac attached to it, with a unique bolt pattern, so no other t-case will work without an expensive adapter.

If you had a T-15 or a T-18 I'd say go for it and have fun. But with a T-14 you're just asking for breakage. I've got access to a couple of used 360's that I've debated putting in the CJ but I just love the 258 too much. It's such a well-matched package that I don't really want to get rid of it.

 

Please decide to restore the 75. The intermediates are a quickly dying breed.

 

It will past everything, but a gas pump!!!

 

Buy the 401 and turn it to fund the 258 rebuild. Around here an old rusted, locked up 401 is going for at least $400 or more (depending on the buyer). With the fact that it's running thats an even bigger bonus. If you can't shift it on the FSJ guys hit up the AMC car guys, there always looking around here.

 

i should mention the $200 is for the whole vehicle. my driveway is full of "projects" as it is. i guess one more won't hurt

 

I would definitely buy that and see what happens. If not, I'm sure a few fellow jeepers around here could find uses for it.

I think I would be in that line

High5

 

junker still interested in what we talked about earlier if it works for you thanks tom

 

tom yep my memeory hasn't failed me yet you have first dibs as we talked about

 

thanks junker

 

I have a low mileage 258.