smoking a top round

[pasmokey]

Kinda a newbie here. i'm smoking a top round for the first time this weekend. It's an 8 pound piece. i'm gonna smoke it to 135 deg and let it rest for a couple hours. My questions is how long will this take to smoke? I've gotten pretty decent at smoking anything pork but have never attempted beef yet.

 

[s2k9k]

I recently smoked a 10# top sirloin and it went about 12 hours to get to 135*.