different then the gen 4 and 5 blocks correct gt?
The Mark IV is commonly referred to as a gen 2.
So quite different from a Mark V and VI.
Gen 1, 2, 3 and so IV refers to the engine family. Once you get to one piece rear, thingsget odd ,gen IV and V are in the same family. MK VI is slightly different, but similar in many ways.
Once you get to LS motors, you may as well be working on a Dodge.
GT