Question on Earls Rear SS Brake Lines

Doing LS1 front brake upgrade and have the Earls SS brake line kit for 98+ F-bodies. Have 2 questions:

1). Will the rear LS1 SS brake lines work on an LT1 car?
2). Any harm in only upgraded to SS in the front only, and keep the 3 lines in the back OEM? Will there be an unbalance b/c of SS in front and rubber in back, or will the ABS adjust for any changes?

Well, I can't answer your first question.... but let me give you feedback on the second.

Rubber flexes.
Braided hose will not flex anywhere near as much as rubber lines.

If you changed from front rubber lines to braided steel lines and left the rear ones rubber then there is a strong potential for more flexing on the rear rubber lines and potential failure.

In my opinion.... all or nothing.

It is well worth it