There are two different articulated frames for the MGA convertible tops, as noted on the prior two pages. The change point was late 1600 production at chassis number 78249. The picture here shows the late model assembly folded back over the body tonneau. The early model frame will stand straight up and lock in place, or it can collapse into the cockpit, but it cannot fold backward as shown in this picture. If you have a top frame in hand you can tell the difference by extending the leg on one side and attempting to form it to the position shown here.

Many parts suppliers list only one part number for the MGA convertible top frame. If you need to know which one is offered you should ask before ordering, but this will most likely be the more common early type frame. If you want the later style top frame, Bob West in the UK has a fabricator-supplier for the newer type frame. There may (or may not) be other sources, but I have no further information at time of this writing.