garage door input needed.

[nwmod39]

good evening to the board.
i am looking into getting a new dorr for my 24*24 shop and get rid of the 2 single doors in favor of one 18 foot door. right now i have a fairly low roof clearance at 7'4" and would like to maybe raise the cross beams in the front half of the shop to accomodate a taller door. i need to gain roughly 8" to get my truck to clear the door while it is open.

i need to hear from some guys who have experience raising the cross beams so i can do this. i am going to take a few pics later tonight to show what i have setup right now but any input ahead of time would be awsome.

thanks