'80 ls swap info needed

[ofnaman]

I'm gathering parts to put a '11 l96 6.0 and 6l90e in a '80 2wd stepside. Already have the engine/trans/sensors/harness/ecm/etc. I'm about to start building the conversion mounts for the engine and I don't know if I should put the engine in the stock location, or move it forward or back a little. I spent all weekend skimming as many ls swap threads on here that I could find, but could not find info on that. What are your thoughts on it? Thank you