Fotoguy20 - a correction: Richard Paine, on page 39 of "A Review of Graflex", lists the lenses for all of the sizes of the earliest Speed Graphics. For the postcard size, the B&L was the f:4.5 Zeiss Tessar Series Ic #15a, which has a 7 1/2 inch focal length. The Cooke Ser II, f4.5, was #21 1/2. The Zeiss Kodak Anastigmat was f6.3.
eworkman - yes, a 3 1/4 x 5 1/2 format Speed Graphic. It would take a dual cut film holder that is about 4 7/16 x 7 1/2 inches, outside dimentions, but I have never seen one of these. ( A regular 4x5 CFH is 4 3/4 x 7 1/4 or so).