Replacing 258 with 4.0 Liter

Hello

I had a question about replacing my 1975 CJ6 258 I6 to a 4.0 liter wrangler style block and head.
I have a stock three speed in the CJ6.
Would this swap be a major problem as far as steering pump, alternator, brackets, mounts etc? This is a later model 4.0 liter short block and head only, no peripheral stuff.
I looked for threads about this swap and may have been using the search engine wrongly.
Any opinions would be appreciated.

 

The nose of the 4.0L crank is different from the 258 (shorter IIRC), so the accessories will not bolt on and be properly aligned.

Why not install the complete 4.0L in place of the 258? There's an entire forum about the 4.0L swap - http://cjoffroad.com/forums/forum.asp?FORUM_ID=24

 

Thanks for the info. What I saw for sale was a block and head and valve cover for a 4.0 liter engine.
I just wondered whether it would bolt up easily to my stock three speed and if I could use my 258 HEI distributor and 32/36 Weber with maybe an aftermarket intake manifold and exhaust, maybe a header. Also wondered about my 258 alternator, brackets, power steering pump, motor mounts etc. bolting up.

 

The accessories brackets mount differently on the 4.0 vs the 258. They are not interchangable.
Motor mounts and transmission bellhousing patterns are the same.

 

The distributor will work. The Weber will work if you fit a '81 or later Jeep 258 2V aluminum intake manifold. You'll need to use the 4.0L exhaust manifold, which is like a header. There is no provision for a mechanical fuel pump on a 4.0L block, so you'll need an electric fuel pump.

 

As Tim said, the distributor and carb can be made to work. The accessories will all need to be 4.0L stuff as the 258 stuff wont' work. There is an alternator that can be made to work with the serpentine belt, I believe it is an older MOPAR part. There's a thread on Pirate about a guy building a carbed propane-powered 4.6L stroker: http://www.pirate4x4.com/forum/showthread.php?t=784954

Sort through the typical Pirate B.S. and you'll find some good info in that thread.

To be honest I think adapting a carb and distributor to a 4.0L to make it work is more trouble than it's worth and is regressive engineering. The OBD I version of the MOPAR fuel injection on the 4.0L only need 5 wires to run and has been thoroughly documented on the net. The OBD II is slightly trickier, but I have an OBD II in my Scrambler and it's amazingly simple as well.

 

The Pirate thread is very interesting.

At work now ... must stop reading...