There is a rattle in the motor. When idleing there is an internal rattle.

could be a possibility. Clanking or rattling: Loose internal mounts can cause rattling and clanking from the compressor. The sound probably means that the motor has come loose and is moving around inside the sealed compressor can

If it rattles,timing is too far advanced.Loosen the distributor bolt,Back timing to fastest idle,and advance it just a little to where the idle is changing slower.Not much tho.Lock the distributor bolt and drive it.If still rattles,do it again till it doesn't rattle.The rattle you speak of is called engine nock,because it's firing ahead of time too much.

Could be worn out timing chain guides

Listen with a stethoscope to the front motor cover

SOUND'S LIKE YOU COULD HAVE A BAD ROD OR CRANK OR LIFTER.TRY THIS CHECK YOUR WATER AND OIL NOW START THE ENGINE IF IT IS A FAST KNOCKING HOLD YOUR FOOT ON THE BRAKE AND PUT THE CARE IN GEAR IF IT QUEITS YOU HAVE BAD ROD SERIOUS MOTOR REPAIR INTERNAL.DO THE SAME THING AGAIN AND IF IT IS MORE A THUMPING NOISE AND A SLOW DEEP KNOCK THEN WITH THE ENGINE IDLEING PUT IT IN GEAR HOLD THE BRAKE GIVE IT A LITTLE GAS AND IF THE MOTOR KNOCK'S GET'S QUEIT IT'S POSSIBLY THE CRANKSHAFT ANOTHER INTERNAL PROBLEM MOTOR OVERHAUL IF IT'S A FAST RATTLING IT'S PROBABLY A LIFTER STUCK OR BLEED DOWN DIRTY OIL OR A WEAK OIL PUMP ALL ARE BAD NEWS SORRY.GOOD LUCK

hose rubbing in next compartment where battery is

This is kind of hard to judge without hearing it. Lets say the noise is the pellets in the Catalytic converter that some types of automakers used, with low flow at idle, the loose pellets can bounce around until the flow increases and pins them to the insides of the Catalytics.

However, if you rebuilt the motor you would know some mechanical stuff. I can move on to more possibilities.

Oil pressure starvation can make the pushrods rattle in the rocker arms. The engine oil pressure will cushion the critical area between the rocker arm and the pushrod seat.

On the rebuilds, have you worked on the heads? Like valve spring tension and pushrod clearance? I have had engines that would idle perfect until accelerated and return to idle clanging and missing. The valve springs were shot. Then I have had some GM motors that had hydraulic lifters yet the pushrods were different lengths and that is how the pushrod clearance was made; by changing individual pushrods to get the correct clearance.

This is something that can occur when the valve seats are cut. The valve stem can ride up into the head slightly when the seats are cut.

Now you may have replaced the camshaft or the lifters or not. But it is recommended that each lifter is paired with a camshaft lobe. If you mixed the lifters into different positions, you may have distortions that are resulting in noisy clearance problems. For that matter, camshaft bearings may be loose.

The Jeep and American Motors cars used a 232 CID engine too. Can't say what components were different but you may have mixed parts.

Now some models used a Rattle or knock sensor, and in the old days, you could get a rattle from weak distributor springs in the breaker plate. The mechanical advance would throw out too fast.

I am curious. Would like to know what you found.

Hope this saves you a heap of dollars.Nearly all jeeps get a rattle from the cat/converter in the exhaust pipe.Crawl underneath when the motor is cool and give it a few good whacks.you might hear it rattle.Other than that,if you bring the revs up and it stops,it is the cat/conv.The internals of the cat. fall apart and rattle around at idle.When the revs pickup,the exhaustflow keeps the internals from moving around.I have seen this very often.I hope this is your problem and not the trans.Hope this helps

muffler strap broken?
motor mount,top on left side of engine broken?
cat rattling?
heat shield?

this is easy one if you put the a/c on do you hear the rattle if yes then shut off the a/c if the noise go away then it is the compressor