[InvisibleChurch]

don't older cars need a leaded attitive to run properly?

[InvisibleChurch]

a leaded additive might work, too

[org.whodat]

NO, you just have to have hardened seats put in the heads for the valve to seat on. However if you have a high compression motor then you do need an octane boost.

[IYAS9YAS]

Not really. The lead acted mostly as a lubricant for valves. If you install hardened valve seats and stainless steel valves, you won't have any problems running unleaded.

I have an old 51 Chevy pickup with a 58 235ci straight six in it. Been running unleaded with no additive for over ten years. Still runs fine.

There are lubricants out there that don't contain lead, but do the same job. Also, most of what the older cars really needed was octane because of higher compression levels.

[Freedom4US]

"don't older cars need a leaded attitive to run properly?"

For years Tetraethyl Lead was added to gasoline to raise octane - it also has the effect of providing lubrication to valve guides and valve seats.

Engines designed for leaded gasoline can be used with unleaded fuel with no ill effect provided engine RPM's are kept low, just poking around the back 40 every now and then, say. Any type of highway use will rapidly erode the valve seats, or can. Most people install hardened valve seats at engine rebuild so as to take unleaded gas.

There are "lead substitutes" available to add to the fuel, but iirc a major auto magazine did a test on the various brands available and came to the conclusion that they are of no benefit unless 4 to 6 bottles are used with every tank.