Exactly what do you expect to see ?
The only time I run an engine with the rocker cover off is if I suspect the breather is blocked causing the crank case to over pressurise and make the engine smokey .
IT will make a big mess
It won't hurt the engine
Thanks for advice valve work is a new one for me . It turned out to be a intake push rod slipped out of place during to overheating im assuming the heads where covered in dirt and hay,weeds,oil i cleaned them thoroughly.