This engine has been sitting for 20 yrs after rewiring the whole car
fixing floor pans started replacing alt fuel pump rebuilt carb etc.
Take her to work and she runs strong. Its the long trips and she starts
acting like she needs a tune up running rough at idle and then I hear
something clanking when excelerating rod knock VALVES? Some of the members suggested adjusting the valves and it got me thinking how do
I even know that this engine has been ever rebuilt to begin with? Could
the unleaded fuel have something to do with it? Maybe dump some additive
in the gas to see if it cures the problem.

_________________
Since I bought my 63 my guitar
has taken the back seat.

Additives won't cure problems -- only make problems (waste your money, foul your spark plugs).

Here is the valve adjustment procedure.

"Knocking" can also be fuel pump, can be loose torque converter bolts...need more specificity.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Have been going to Napa for parts dont trust auto zone .How do I
really know if this engine has even been touched and those valves
are screaming for some leaded fuel?

_________________
Since I bought my 63 my guitar
has taken the back seat.

Playing baseball in a slant six game ,I thought I hit a double ,was wrong
coach told me I got hit with a foul ball and to go sit back on the bench

_________________
Since I bought my 63 my guitar
has taken the back seat.

If the valves are damaged enough to start showing symptoms from lack of unleaded fuel, the valves would be cracked or other wise damaged. A simple compression check would test this.

Valve adjusting is a normal periodic maintenance procedure typically done every oil change. You should just do it.

If you want to know the condition of your motor, do a compression check then install an oil pressure gauge and a vacuum gauge and observe them while driving.

You want cylinder compression generally above 110 PSI and within 10% across the cylinders. It is normal to have some variation, but you want the readings to be within 10% of each other.

A stock slant six should get 17-20 inches of vacuum at idle. The needle should be steady.

You should see around 35-50 PSI oil pressure at first startup, it should settle down to anywhere from 5-25 PSI hot at idle, and it should go up when the RPMs increase.

It doesnt matter if the valves have ever been adjusted...it only matters if it needs valve adjustment now.

Go buy a new valve cover gasket and a set of feeler gauges.

_________________
Yeah....Im the one who destroyed this rare, vintage automobile.....

You do not need leaded gasoline. You do need a valve adjustment every 20,000 miles or so. Go do it. Also, get the three books described in this thread as quickly as you can.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks guys , will roll the dice and adjust them and if it works great
if not at least I will know what needs to be next. Its been a great day
for being lucky I work third shift so went over to pick n pull looking
for that 69 valliant but ran across a 63 polara and started to drool all
over myself heater core was bad but still got alot of goodies and my
brother in law told me when I got the car that I could run across one.
I take back what I was thinking about him.

_________________
Since I bought my 63 my guitar
has taken the back seat.