The first Pacific game is one of the best A&A games in the series IMHO. One thing that is a little frustrating is how Japan has a big advantage OOB. In doing some research on balance, I found 2 really good sources to help me with making up some house rules for balance. Here are the two sites that I found most helpful for my following house rules.
Saburo Sakai: http://www.axisandallies.org/forums/index.php?topic=7581.0
Axis and Allies Pacific House Rules
1. Japan wins by receiving 24 victory points.
(Japan can capture enemy capitals, but it must reach 24 victory points to win the game)
2. Allies receive 12 IPCs to purchase units before or during the first round.
(Allies need help in the beginning of the game, especially in India)
3. If Japan attacks sea zone 5 in the first round, it scores no victory points on that turn.
(It will be difficult for Japan to lose at least two carriers in a counterattack and hold off the Americans. This also reflects a higher level of anger and shock for the USA)
**4. Kamikazes activated if Japan drops below 30 IPCs. **
(Kamikazes were a desperation tactic used by Japan when they were losing the war)
5. Attacking subs must fight one round before submerging.
(No substalling allowed. Larry Harris did not intend to have substalling)