[maxpain43]

I'm not sure, I think you can't do that. what you can do is increasing speed as CJ walkstyle then any other running cause that walkstyle is the fastest.. (increasing speed of the game is probably something you saw by cheats?)
https://sampwiki.blast.hk/wiki/UsePlayerPedAnims - For CJ walkstyle.

https://sampforum.blast.hk/showthread.php?tid=334339 - Filterscript to increase vehicle MAX_SPEED.