Are the cross members different on the L 48 and L82? A vendor asked me if the exhaust  pipe pass thru holes were close to each other or were they spread furthur outboard from each other.He and I were talking pre bent pipes at the time.

They're the same.

There IS a difference between the automatic x-members, and the standard ones....this is probably where the question comes in.

I suspect he was asking if your pipes come together on one side of the car like stock 77s do, or if you had true duals like the 74 and older.  Your crossmember should have the two holes for true duals if you want to switch to them.  The only thing you need besides a set of '74 pipes is the special adapter center exhaust hanger.  There is a good one made by taking a 77 style single hanger and welding a second hanger to it, and there is a cheap one that is simply a generic hanger you screw to the crossmember.  While there is a difference between the crossmembers, the space between the pipes is exactly the same on automatic and manual crossmembers.

Larry