Keep in mind, there were two 3.8 liters, the Buick derived version which started life in the early 60's and morphed into the 3800, 3800 series 2 and 3800 series 3. It also spawned the 3.0 and 3.2 V6's. The Chevrolet version was the 229 (305 with two cylinders missing) and it was a POS.
Swapping EFI engines is easy - there are many websites and manuals that step you thru. If you can wire a horn or starter and have the basics of reading a wiring diagram, your 90% there. The rest is still cut-to-shape, hammer-to-fit, paint-to-match.