Hi Derry, from what I understand you should at least consider getting your radiator re-cored. That's quite a tight engine bay and the 350 will need all the help it can get.
I'm doing the same thing with my '50.
Regarding the trans cooler,i'm putting a remote one mounted in the chassis,or possibly in the void between the rad and grill.There are loads of options.
I haven't decided yet.
Someone else will chime in with more advice soon.....

Jock

1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.