There's nothing new to consider due to your gear change...the tuning should be the same. You're more likely in a useable powerband with your new gears. These old trucks were not intended for today's freeway speeds, they were meant for hauling hay around the farm. There's generally a lot of potential for tuning if you enjoy it, otherwise run it as it is.
I tune race cars on the side, and have applied the same things to my truck to some degree. It was getting 12 mpg, now I'm up to 20 and still tinkering with it. I have the same 235/ 1bbl combo you do, but I have 3.55 gears.
Devin
