The Daytona schedule and entry list(s) are available at
http://www.amaproracing.com/news.cfm?cid=20458&rr=no
Nothing says "thursday afternoon" like a Superbike race.
As far as I can tell, the only race that's being shown at all by Speed is the 200 (minibike race as Mladin refered to it).
Looks like no coverage at all on Thursday and 8 hrs of live Nascar practice on Friday interupted by the 200.
http://www.speedtv.com/schedule/filter/date/2009-3-6