when using a timing gun setting the timing i should set it to tdc or befor or after im not sure how should the timing be set thanks

 

If you set the gun to 0* you will be looking for the red middle mark on crank pulley. If you set it to i think is (16* for gsr not sure or whatever it is) itll be the white mark. No diffirence. Just set it to 0* and align it with the red mark.