exhaust pipe cross ref...

just want to find out if i can use the 4 in to 1 header pipes off my "81" honda cb650 for my 77 650b-1.
anyone know of where i can find a chart or something to find out if spacing is the same for both bikes?

I highly doubt there is a chart for interchanging exhausts. You could just measure it. Just measure from the center of each pipe to the center of the next and measure the OD of the pipe to see if it'll fit up in your head. I think those may be the only 2 things you'll need to measure to see if it'll fit.