When setting the timing you find top dead center by bumping thr engine over until air blow out around your finger. Then take a socket and breaker bar line up mark on 10 BTDC. Pull cap to see where rotor is pointing. Make sure plug wires are correct at this time. Here is a diagram of a Chevy V8 points distributor Google Image Result for http://ww2.justanswer.com/uploads/ASEMaster35yrs/2010-03-17_090540_chevy_v8_firing_order_diagram.jpg
It should be close enough to start and set timing.