Hi all

I know this has been discussed previously, but I ran a search and it looks like it has been cleaned out.

I have a 1977 Datsun 1200GX.
In South Africa I have heard last night that in 2005 leaded fuel is going to be phased out and by 2006 only unleaded fuel will be available.
My questions:

1. If our unleaded fuel are not compatible with my engine.What damage will it cause.
I do not want to remove my head now to prepare it for unleaded.
I rather want to keep driving it until the valve guides are worn and then convert the head to be able to handle unleaded.
Is only the valve guides going to get damaged?
What simptoms will my datto have to show me this occurince.
2. Those of you running unleaded, did you have to reset the timing?
3. Catelitic converter.
I have talked to lots of exhaust shops here and no one is using catelitic converters here.
One guy said "we just take them off and cut the sencor's wires that are plugged into them".......WHAT AN ASSHOLE!!!!!
My dad drives a 1995 volvo 850 and did some research for when his exhaust goes and this was one guys answer.
Someone else said they butchered one open when it was removed and saw it looks like a normal exhaust.
They just put in another exhaust box and drill a hole in it for the sensor.

I know our datsuns don't have sensors.
Must I then just put on another silencer?
thanks