Transmission cooler or new rad?

[Canadac10]

Not sure if this is the right section to post, but here goes. In the process of swapping out my 3-speed Saginaw for a 700r4. Going in a '70 C10. Transmission shop is doing the swap for me but I need to address the transmission cooler situation. Truck originally had the I-6 but now has a SB350 out of a 1980 Vette which has a mild cam in it. Original rad, re-cored probably. If anyone has similar experience is it worth it to go with the existing rad and ad a trans cooler or pop for a nice after-market aluminum one that can handle both. At this time I don't have any plans to build the motor beyond where it is. Thanks for any advice!!