1991 K2500 5.7V8: MT35845A vs MT34585

[DTG_]

Driving down the highway and tranny gave out. Was a rebuild from a shop 6 yrs ago so mighta been long time coming, but need to replace. Manual says these 2 are possible 5-speed manual options. Looking the 2 of them up I can see one the 35845A includes the bellhousing and the 34585 doesn't. Are the 2 interchangeable with the '91 K2500? If so, are there any adapters or alterations necessary going from one to the other?

 

[Erik the Awful]

What transmission do you currently have?

 

[DTG_]

Current install looks like the integral bellhousing. From what I can tell tell the integral bell housing tranny has 8-10 mount bolts for the bell where the non-integral is only like 4