1938 Dodge pick up!

Small blocks should fit without too much trouble. I've seen a '37 with an early hemi in it, so I know it can be done, but it would definitely require a lot of fab work. A small block shouldn't be bad, the nice thing about the old trucks is that the frame rails make it pretty easy to add engine mounts.

A Dakota frame would itself need a lot of modification to even fit the body, the Dakota frames go well under '50's era trucks, they would be too wide and too long for a '38. You could do a Mustang II front crossmember, I've seen them made for this application.

I'll be keeping the straight axle in mine though, there's a few kits available to convert the stock front end over to disk brakes.

Nice looking truck though, looks pretty solid in the pictures. :-D