I don't think my part numbers will be helpful. We have different set-ups. Browse the brake parts at Speedway. There are different connections in and out of the pressure switch. You need to match the connections to your brake line size.
Your sending unit will be different than mine, I have a C-4. As Jim mentioned, the new sending unit will attach in the Tranny where the mechanical sender is now.
Also there are different faces for Stewart Warner Gauges, you need to check to see which style you have.
Try:
www.speedwaymotors.com
Also:
http://www.stewartwarner.net/
The latter has more choices for gauges. My advice, call both. Speak to a Tech and tell them what you are doing. I found them both to be helpful.
Hope this helps.
Regards,