Gorgeous truck, RB!
The gang has good advice and it seems you are going in a reasonable direction. If the gang here takes your posts and moves them around, please know that we do this only to facilitate you getting the info you need. It's done to help. The few rules we have here are designed to help, not to hinder, so don't let them slow you down or inhibit you. We're just trying to help. The rules serve us, not we them.

On the sixes ("Six in a row makes it go"), even a 235 would make that truck cruise nicely with the T-5 and a good rear (that the resident gurus are advising you on).
It continues to amaze me that with only a few simple tweaks, that don't destroy the originality, these trucks can become far more modern road capable. It doesn't take much!
Welcome to our site and we're glad to have you aboard. From your past, it sounds like you have been around the block a few times -- don't hesitate to share what you know. We're all here to learn.
And did I mention that your truck is gorgeous??
Regards,
John