Arms like the # LC759516 are designed for an 8' extension. These measure 63" just like what you had. The # LC434723 with 69" arms is also made for an 8' extension. As long as you have 69" Of unobstructed space from the awning rail straight down and 2-1/2" of clearance between the awning rail and the top of your entry door you can use the longer arms. view full answer...