GM has always given it's consumers the most interchangable parts on the market all of their engine blocks and trans housings bold up in trucks. parts swap over insanely easy.... that's what made Gm #1 for so long.
They have many engine configurations... very similar blocks but many different parts that go on to make the long block
Heads,Big cam, 4:11, Custom Exhaust, MGW Shifter Baer Eradispeed +2 2 pieces rotors, Hotchkiss swaybars. and a few other little things.
1998 Trans Am A4 ( was STS turbo until the turbo and oil pump died)
2000 WS6 Trans AM under the knife ( sadly turned into long term project.