hey, i just found out i have a 1959 261 with 235 heads which i thought was a 235 as i was told when i bought the truck. anyways im in the process of installing an hei dizzy i got from langdons and it tells me to rotate the engine to 10-18 degrees before top dead center, the tdc mark on the flywheel is a indented circle, right before the circle there are two lines an inch or so apart, a couple inches before the lines there is a triangle. where exactly is 10-18 degrees btdc? and what are these other marks?
