The Crosman 1088 Pellet/BB is rated at 400-430 FPS
Crosman says it's rated at 1000 FPS.
See the related link at the bottom of this page to see the Crosman 1088 parts manual.
I believe you are asking about the Remington AM77. It is rated at 725 FPS.
see the link below
450 FPS BB 400 FPS Pellets
It's rated at 580 FPS.
see the link below for the owners manual
360 fps
Sound travels at 1,088 fps.
Crosman doesn't advertise the "Foot Pounds" of their airguns but they do state the FPS "Feet Per Second". The Crosman Phantom .22 is rated at 495 FPS. If you still want to know the Foot Pounds I suggest you contact Crosman at the link below.
It would really help if you stated the manufacture of the 1088. So I'm going to guess it's a Crosman. See the link below
The Remington Airmaster is rated at 725 FPS (Feet Per Second). The Crosman 760 Powermaster is rated at 595 FPS and the 760P is rated at 600 FPS. 10 pumps each.