If you want their 40 time, here is a good place to start:
http://www.nfldraftscout.com/ratings...SC&startspot=0
From there, you can change the year they will be coming out and go to whatever position you are looking for. From some guys I have researched, the information is pretty reliable when compared with other sources.
For Rivals what I do is just go to google and type in the player name and rivals. For example, Jahvid Best Rivals would give me this page as the first result:
http://www.rivals.com/viewprospect.asp?pr_key=52772
It only shows the 40 time for Best but other players you look for may have bench press reps, etc. Do the same with NFL Draft Scout and Scout.com. Player Name NFL Draft Scout/Scout.com