Hot Rods Please ID this ford transmission

I am looking for a ford 4 speed overdrive transmission for my flathead. I think I'm looking for a SMOD.
I have found this out of an 80s f100. What is it?

 

Looks like a granny-low 4-speed....

 

NP435. Beast. Yes, granny low. Superstar 4 speed truck for Ford, and Dodge.

 

No much good for a flathead I guess.

 

Okay
I think this might be one or are they aluminum case?

 

That's a RUG overdrive; based on the Ford toploader four-speed, plenty strong enough to put behind a flathead. There's also a aluminum-case version known as the SROD that has internal linkage (like a T5) that has the same basic internals but is a bit lighter-duty. Again, strong enough for a flathead. Do check both for wear on the cluster gear shaft/bearings as that's their weak point.