i am opening up a wall between two rooms. The house was built arount 1930. the wall was a load bearing wall supporting the roof until an addition was made and the roof was removed. right now the wall is 8'6" long and is supported by one 4x4 at one end (exterior), another 4x4 3 feet from that same end (towards the exterior) and a couple of 2X4X10 6 feet from exterior wall. based on specs I believe i need a header 2X10 to support the 8.6" header length. am i correct? also i would like suggestions on how to brace the top plate while i remove the 4x4 and install the new header.