lt1 in a 70 blazer

[bdas70chevy]

i wanted to get some insight on what i got my self in to i got a 94-96 lt1 engine with no computer or wiring. has anyone had any luck with the painless kit with the com. and the harness together? and do i have to run a return line back to the gas tank, and what kind of gas line should i use? i am trying to get everything set up so there is not that much down time on the blazer, if i can do some things before i take the motor out and stuff the lt1 in it thanx for any insight on the task