Allison transmission into '77-'87 truck body?

[The Dark Side of Will]

Specifically, my dad's 1990 original diesel Suburban.

We're investigating a Duramax/Allison swap and have not been able to find any info on whether or not the Allison fits, and if not what's necessary to install it... body lift or transmission tunnel surgery.

 

Advice or links welcome. Thanks!

[grampadirt]

My understanding is that an Allison is much bigger,meaning you'll have to modify the trans hump in the floorboard.

[The Dark Side of Will]

I'm trying to find an account of it being done to verify that.

[grampadirt]

Have a look at this: http://1973 - 1999 Chevy / GMC Gas and Diesel

 

Crap,link didn't work.I'll keep trying.

 

This one does.

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwiHuP78ge7UAhWFr1QKHReDAjsQFggoMAA&url=https%3A%2F%2Fwww.dieselconversion.com%2Fblog%2FGM-Chevy-1978-1999-Diesel-Gas%2F&usg=AFQjCNEwm4MR95pc6ZYmchLkr4_BSnMADg