set the crank/timing cover timing marks on the initial amt (ie 10BTDC) you plan to run (#1 compression of course) then index the inter gear (wherever) so it locates the rotor under (or very near under) the #1 dist cap terminal w the dist housing located in factory position where the vac can has room to b turned and if you are locating your plug wires from scratch the factory diagram is best for standardization for future reference and it lets the wires nestle neatly w the shortest route and diff dizzys can have diff top rotor slot to bottom shaft tang orientation and the bottom line is you want the rotor blade as close to dead center on the underside cap terminal as possible when it fires and only vac adv will alter rotor phasing from that point (moves it CW on a BB and CCW on a SB) EDIT forgot, turn dist till the magnet slot is dead even w the nearest reluctor tooth then move the housing (magnet) a hair more past the tooth opposite dist rotation w the rotor under #1