Your initial timing should be about 12 to 14 degrees. And it is important to a street car on pump gas!! What I would do would be set my total timing at 34 to 38 what ever you prefer, then work with your advance in your distributor. You can change it until you get your desired intial timing. The intial timing is what you have at idle and the total is what the timing is when your distributer has reached max advance, usually 2500 rpm or more. Your total timing is the most important though. We always lock our advance in on a race cars but pump gas is a whole nother ball game.
Good luck,