Li 150 cyclinders

Hi all
I'm a rare contributor to the forum although a regular reader of its posts. I just wish to check with members something that I think I know the answer to but would like confirming. Basically, is there any real differences between a Series 2 150 cylinder/piston and a Series 3 150 cylinder/piston? Are they, in effect, interchangeable? Thanking you in advance
I'm a rare contributor to the forum although a regular reader of its posts. I just wish to check with members something that I think I know the answer to but would like confirming. Basically, is there any real differences between a Series 2 150 cylinder/piston and a Series 3 150 cylinder/piston? Are they, in effect, interchangeable? Thanking you in advance