Shift Points & Max. Timing?

I have a new Ford Racing GT 40 B-303 cam 345hp crate motor in my 93 GT Mustang.
It has about 550 miles on it.
I have the timing at 15 advanced, fuel pressure 39psi.
The best I've run so far is 13.4 @ 102 mph in the 1/4 mile.
I use to run 15 advanced timing on my old 5.0 motor which worked well.
Will I gain anything by upping the timing some more on this motor, or is this as high as I should go?
I have my shift light set at 5500 rpms. It sounds and feels like a good setting. Does that sound like a good shift point?
Thanks

I'm using Hoosier Quick Time Pro's. They're a Dot class slick basically.
60' aren't bad. Should be better. 1.89. The car actually hooks so hard that it bogs sometimes. Even launching at 4000 to 5000 rpms. I just keep upping the pressure.
It's been better with 22 psi , I may even try 25 and see what happens.
Compared to my old 5.0 , this new motor keeps pulls more at higher rpms.
My old motor 5300 was a good time to shift.
I use to run drag radials too ,so the Hoosiers are new to me.