Help on Drop Kit?

[ap2002]

i am planning on ordering a 2/4 drop kit for my 68 but now this is my concern, as of now my 68 has a 454 big block in it, it will be replaced with a 5.3/6.0 in a year or maybe a little longer, but this is my question.... they sale 2" drop springs for big blocks and 2"drop spring for small blocks? what is really the difference.... if i buy the drop spring for the small blocks, im guessing witht he 454 in there its going to drop it more than 2"? if so, how much more? i just really hate to change out the springs again when i get the LS motor in there in the future...

any help is appreciated..