EEC_1981

Hey Im new to this site and I need some info please. I have a 77 620 with an l20b and a five speed and I need to know if I can swap it into an 83 king cab 2wd that i recently just got. It had a z24 with a 5speed but both the motor and tranny are shot but the truck is real nice and worth saving my 620 on the other hand has a good motor and tranny but the body is shot and rusted out. Anyhow it looks close but the motor mounts look different any info would be appreciated thank you