Low Water Pressure in tub/shower only

I have very low water pressure in my tub/shower. Water pressure is good throughout the rest of the house, including the sink in the bathroom. I have a two handle set up with a spout diverter for the shower (American Standard Cadet 3275). I replaced the hot and cold stem valves (American Standard 954120-0070A).

I have turned the water on without the valves or handles and have great pressure coming out of the pipes in both hot and cold water. After I put the valves and handles back on the pressure coming out of the spout and shower is still very low.

I replaced the faucets/spout/shower head about 5 years ago. Do not have a clue on what else I can do.

Thanks for your help.

Sounds like you've isolated the problem. You need a update on you valves.