Brake issues!!!
 

Just installed new pads and calipers on the front and it stops worse now than it did BEFORE the new parts. At 35 mph I can stand on the pedal with both feet and I'm 6ft 2 and over 300 lbs and it will not even lock up the wheels. Shop said all the air was bled out fine and no glaze on the rotors. Someone asked me about pad shims. I did not see any and the parts store said I did not need them. Any ideas? This is on my 96 B2500 conversion van.

Check the brake booster, check for vacuum leaks, adjust the rear brakes, pressure bleed the system, change the hoses, etc. I'm not sure you can lock up the wheels when fully loaded unless the road is wet.

Is the brake pedal going to the floor or is it just a real hard to press pedal?

No the pedal does not go to the floor but it needs pumped to stop better. Local mechanic said he hears a hiss coming from the booster when I step on the brakes. I go NOT hear it. Funny thing is they work GREAT when backing up. Another thing. My brother in law who changed my pads and calipers said the old pads had shims that he did NOT use. He said O'Reilly auto parts guy said that the new ones did NOT need them!!!!!!! I DO NOT KNOW!!!!

Calipers generally don't require shims. The thin plates you see on the backside of the pads are usually anti-rattle/squeal clips.

Pedal height (where it actually starts applying the brakes) is controlled by the rear brake adjustment. If you have excessive travel before the brakes actually start doing something, I would take a good hard look at the rears, and make sure they are adjusted properly.