The great stroker discussion!! 4in or more

Ultimately you can change the rod length if you wanted to. Most come with the stock rod length but also sometimes it will have a slight adjustment in length.
6.0, 6.125, 6.250 are possible.

If it is in a kit, the length should be listed in the ingredients. LOL
The pistons within the kit should not have an issue working in the block (height) or with the rod.