E-350 Tranny Swap, PLEASE HELP
 

Ok, here goes. I have a 1988 E-350 Grumman Kurbmaster. 4BT with Borg Warner T-19. Top Speed 54MPH. YES I said 54! I have done a ton of research and just need a clarification.
I have access to a ZF S 5-42 from a 1992 2wd F-250, 351W. No speedo cable as 92 and up speedo was diff driven, but no big there. Smartphone has a speedo.
Since 4bt has small block Ford engine adapter,......
1. Tranny should bolt up? top bolts 5.25 on center both trannies
2. ZF has internal slave, any advice here?
3. about an inch longer, prob have to shorten driveshaft.
4. Input Shaft is bigger, so new clutch (pressure plate as well) right?

Any1 done this swap? This van gets 16MPG so can't afford for it to be down long. I am comfortable with minor fabrication and my research indicates could be a one day swap, or one day and re-install the driveline the next

Any help appreciated. And yes I have looked for a specific thread for 3 hours today, no luck.

Thanks in Advance! Josh