Yes - it won't cause any problems.

After all this discussion i'm still a little lost. Can someone tell me if I can run unleaded in my A12? Sorry i'm not very mechanically minded.

yeh im pretty sure the manifold is cast...

Sure does I think they called them log heads because they are heavy ,I bet the manifold is cast onto the head .

hey all sorry for runnin off topic heeps...
why are they called the log head.... this motor dosent miss a beat!
so being cast iron that means i MUST use the flash lube right?
thanx

250 precrossflow. Yes cast iron for sure.The ole infamous log head.

If your Jeep is running a pre-crossflow Ford 6 the head will be cast iron.

1200GXman
Firstly, i think you are writing "valve guide" but really mean "valve SEAT" This is the round ring that is inserted into the head & is machined so that the valve can seal the combustion chamber.
The valve guide can be seen up in the port & the top of it protrudes into the rocker area. These are to guide the valve as it moves up & down.

If you do suffer valve seat recession, the tappet clearance will close up, eventually to nothing. Then the engine will run rough, & if you keep driving it, you will likely burn out one or more exhaust valves. By this stage you will need to pull the head off for repairs, to find that they have NOT eaten their way into the aluminium.

Woody
You can not legaly buy leaded super grade fuel in NSW. I suspect that you are using "Lead Replacement" super, the same as I do. If you read the label at the bowser [fuel pump] in the service station, it will say "lead replacement". It is now being phased out by some companies.

my jeep runs on leaded ( super) but i cant remember what the head is made of..it's a 250 falcon.. 4.1 non X flow, ne 1 now wat the head is made of... ne way it runs on super... and we do a bit of travelin and not every servo sells super... so we carry this little bottle of " flash lube" ya mix i think it is 1 mill of the stuff to a litre... then in the can ur mixin it in u give it a shake and poor it in...... using unleaded fuel...... i dont think it owuld hurt to use it ..

I am thinking of using a specific petrol company here in South Africa.
They have recently launched a new unleaded petrol.
They are advertising that their fuel are direct injection compatible.
This does not have efect on me of course.
BUT. They also state that they have stuff in the fuel that they call "lead replacements" and also state "can be used by most cars that use leaded fuel".

Hopefully they did research on the problem that I will have if I use normal unleaded fuel.

Thanks for the info Dodgeman.
Something else.
If the valves do grind away steadily as you have mentioned at the valve guides due to no lead to protect it, wil it cut so deep that it will get to my GX head's aluminium?
Or is the valve guides too thick so that I will notice that something is wrong before this will occur. For example noisy valves or rattles.