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at idle truck runs smooth, going down the road it starts pinging.
The truck is bone stock, carb, electric fuel pump, and dist.
I went from driving the truck once a month for a garbage dump and hauling dirt. Now I drive it daily.
My question is because lack of money I can not throw parts at it right.

Would you start at fuel pump and fuel filter or vacuum advance?

It sounds like a sports car running on cheap gas which goes away when running good gas.
The last time I filled up, I did put high octane fuel in it. No change.
I believe it is running lean but just start happening.
I have not changed anything recently

I have had the truck 8 years and the only thing I have done it clutches, coil, voltage reg, alternator, spark plugs, points spark plug wires, and brakes.

which I have never changed points before, I changed points about 3 months ago, hope I set them correctly but it is was points I would think I would have had a problem before now

Should also include no noticeable change in horsepower...haha 1.8 but I hope you know what I mean

Did you check the timing? Points wear out. The timing in my 75 drifts slowly.

replaced cap and rotor, starting to run alittle better. I guess I screwed up the points. After 3 months very little left of the pads. Going to swap out points and time it this weekend with a friends help. Hope he can teach something about points

replaced points with friends help. checked timing, it was set to 13 degrees, we both thought that was a little high. I thought it would be set between 5 and 7 off the top of my head. We lowered to 10 degrees. Ran better when setting there running. But driving it seems to have less horsepower. the pinging is worse now. I guess change it back to 13 and see what happens. I do have a little valve noise too. Time to rebuild the motor I guess.

I had what sounds like a simular problem. Try a compression test. mine blew the head gasket between 2 cylinders. Not to difficult of a fix. There is some posts on here from a while back that include great pics.

interesting thing happened, changed points, changed cap and rotor. adjusted the timing. it seems like it likes about 13 degrees. Now crazy thing. Temp gauge always read right on the normal line. Now it is running cooler. I opened the radiator cap while the truck was cold to see if the thermostat was stuck open. I didn't see any water moving so it appears the thermostat is closed all the way. I know if it was running hot to look at the water pump and belt or head gasket, water level, or radiator cap. But with the truck running cool, I don't know what else to look at. Any ideas?

These trucks stock have low enough compression that it is difficult to get pinging no mater where the timing is set. Like Ken said--I think you have a blown head gasket between two cylinders. If it was timing related it would get better with the timing retarded not worse. It can also sound like a loose valve adj at low speed. Check your compression in each cylinder, if two are low and next to each other that would be the problem. Water leakage or overheating will only occur when the gasket is bad between the cylinder and a water port.

what should the compression be? seems like 100 to 125 seems to be good on most cars but I have no idea with this truck

Thank you

If I recall correctly 130 lbs sounds about right. More important is the variance between them.

spark plugs are white, Really white so it is running lean.
compression is
150
110
120
120
First compression test I have ever done.
I did it cold and dry. I did not add any oil to the cylinders.
I guess there are some different idea on this subject so I just threw it out there.
I am going to get a fuel filter today and see if it fixes the lean issue.

For consistency, I'd do it with a warmed up motor with all the plugs out and the throttle completely open for each test.
Then repeat with oil in the cylinders.

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