Being new to the world of classic cars, I have a question regarding running unleaded gasoline in a 1970 AMC Rebel that was designed for leaded gasoline.

How will this affect engine performance, wear and tear, etc.

Thanks for responding

For performance I don’t think you’ll have a problem as long as you’re using a premium fuel of 98 or higher octane.
As for the lack of lead that all depends on whether this engine’s cylinder heads were or have seen a reconditioning and received hardened valves and valve guides? How to tell I’m not sure?
I can still remember; for example when GM started to put catalytic converters on their vehicles and had to use unleaded fuel.
They or not too many people didn't realized that the lead in the fuel also had a lubricating quality. Without the lead the valve stems were being chewed out at relatively low mileage of 30 to 50K.
Once the heads were reconditioned with the hardened valves the problem seemed to disappear.
I’m not an automotive machinist and I’m just going by what I remember but we had to have a lot of cylinder heads rebuilt back then and after they were reconditioned the problem didn’t return.
There are top end lubes that can be added to the fuel tank; some are just snake oil that will do squat; some are not bad, but anything that claims to add intake valve lubrication is better then nothing.
Dan.

Canadian "EH"

Thanks Dan. This is what I thought. I just wanted to hear it from someone smarter than me. The engine has never been re-built and is all original.

Mike

The lead also helps seal the valves too! Maybe even cylinders. I think even if you do have hardend valve seats lead won't hurt and could still help. Just don't use lead at the same time you use an oxygen sensor. It will also clog up a catalytic converter if you use one. To avoid the snake oil brands of lead additive I would say make sure you get one that has real lead.

if you are going to use this car much have engine mods done diff valves andhead gasket and convert to photo cell ign easy to do hard for judge to tell if you go show for point pr just ad lead sub from parts store the ping you hear is is going to worse set back timing hurt permorence talk to engine machinist

Lead IMO was just a cheap way to boost octane rating. Otherwise it hurt everything. Before "unleaded" was mandated there was "white gas" used for marine (still automotive engines in many cases) and we would flock to buy it for off season storage as it didn't gell up like leaded did. It's hindsight now. I still maintain we were lied to about "tetra ethyl lead" being good for anything for the car itself,

T
Tom Greenleaf - MetroWest Boston - USA
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http://www.autoacsystems.com/tomgreenleaf/