Projects Flat head for 1941 PU

What flat head came in 1941 Ford PU ?

And what Flat Head, would you replace it with, that has better performance. And are there any conversion to a automatic transmission to Flat Head ?

 

put an early 50's flatty and check out speedways adapters for auto's of your choice.

 

Put an 8BA flathead in it. There are plenty of options for transmission adapters, like hotrod-linkin already said speedway has different options.