Mike:
As stated later by Chris Tompkins in NZ the Convertible, Woody and Pickup frames have extra large holes in the heavier gauge x-member. These model frames also have a single thickness around the anti chatter holes. Your statement that after mid 1939 they all had "doubler plates" is absolutely wrong and I have many 1939 and 1940 examples here that differ..........Larry
Larry, First and foremost, I have a ton of respect for you and subsequently your knowledge of these vehicles. I always appreciate your advice and insight. It's apparent we have both have a lot of different experiences. Keep teaching my friend, keep teaching. That being the case, I just went and checked the frames that I
KNOW are either convertible, wagon or pickup. Here's what I found: '39 wagon, VERY early production has the extra holes you describe. 1940 pickup had the extra holes you describe. Three 1940 convertible frames, one has the three holes, the other two do not. One '39 convertible frame had the extra three holes.
Extra welded plates at the stiffener? All of the 1940 frames had them. Only the 39 convertible did as well. The 39 wagon, once again is a very early car and thus did not.
This teaches me, well, reminds me, once again that Ford did some strange things and did not always do everything (respective to a particular part) identically.
I make the mistake of using "always" way too often. This "lesson" was good smack in the head to not do that.