mdf only comes 4 feet wide.....
True. But it's 8 feet long. Turn it sideways.
A quick look in my '62, and I think I can use one sheet for the driver's roof and the excess for the short piece at the back doors, then one each for the middle sections.
That buys several more sheets than you'd guess for the project, but I still think it's the hot ticket.
I'll be doing it in mine this summer.
Also, I put stick-on Dynamat on the roof panels--without it, the ENTIRE roof oil-canned something fierce every time I hit a bump, pot hole or rair road track. It NEEDS something like dynamat stuck to the underside of it. I'll put another layer of closed-cell sound deadener between the headliner boards and it, so I'll have a very quiet roof.
-Brad