i took my header off to get them patched up and i found some oil in the exhaust chamber pull the spark plug and there's no oil spot anyone have any idea what this could be i was leaning toward valve seals but i am not sure anyone know???

 

valve seal. How much mileage is on that head? If the valve to guide clearance is out of spec from wear, changing the valve seals will only solve the problem for a short time before it starts leaking again.

 

about 60-70 percent of my customers heads needs new guides when they come in for portwork and valve job. You should really consider taking your head to a local machine shop and have the valve to guide clearence check out.