Thanks a lot for the answer.
My engine is a LT1 95, EFI, with stock PCM, I already have Tunner Cat to work on the tunning. I think that I could try advancing the time and I will change the spark plugs too, I was using stock ones and I read that the recommended for the 503 Cam are TR55 NGK.
For now the plan would be:
1. Bleed the system, just in case. 2. Re-adjust the rear brakes.
3. Check pedal free travel (rod lenght)
4. Apply vacuum to the booster with an external pump, just to try if there is an improvement, if there is, modify the ignition time with tuner cat. (or maybe a dual diaphragm booster?)
5. Now I think I'm clear that updating to 1" master cylinder without changing the stock components was an error, so, when my budget allow me, for start swap to toyota calipers, I already have the calipers for vented rotors, so I need rebuild the calipers, buy the rotors and spacers.
Of course, any other ideas are welcome.
Thanks again,