I am getting ready to run boost on my Blazer, was TBI, converted to MPFI. Look up a stock bin for a GMC Cyclone or Typhoon. Take a look at the spark tables to give you an idea of what you will need to do with timing. You will have to run less timing under boost.

And yes you will have issues if you try to run too much pressure on stock Rochester GM injectors. I tried it with a set of stock LT1 injectors and at 60 pounds they stopped flowing fuel. The newer slim body Bosch injectors will handle over 60 psi of pressure. My LS1 Fbody runs 62 pounds. If you run out of fuel you may try a set 60 pound 350 TBI injectors or even the 454 80 pounders.