Convert from powerglide to 700r4 or t56

[Rob68c10]

Hey guys as of right now I have a 307/powerglide in my 68. It's getting close to that time where I start thinking about drivetrain. My goal for this truck is a nice cruiser. Doesn't have to be a power house. I want something I can drive on longer trips and not break the bank. I have been thinking about doing a very mild build on a 327 I have, or just hopping the 307 up a little bit. However the power glide has to go. I just can't decide between a 700r4 or a t56. Is there a huge cost difference in one swap or the other? This is one part of the build of this truck where I honestly have no major preference of which selection to make and the cheapest reliable option will probably beat out the other. So convince me.