If the conversion was a generator, and not an alternator, the polarity could be either negative ground or positive. If it is chargine and the battery voltage is at 14 or so volts it is OK grounded as is. If it is a generator, and not charging follow John Ts charging system procedure to set the system correctly.
If it is an alternator it is 99.8 % negative ground.
The coil should match the battery ground. Negative to distributor with negative ground.
Point gap is .020 on the high point of a distributor cam lobe. (turn engine by hand to get there)
A coil that says on its documentation that it needs no external resistor needs none. a coil that says "use with external resistor does need one. Jim