I believe my master is junk, I can push the spring in with my finger, plus I have no pedal! So I bought an LS1 master cylinder off ebay for $28 shipped.

Everything mounted up fine as expected. The back brake line fit like it's suppose to, but the front line won't fit. It looks like the LT1 flare nut is smaller than the LS1 fitting...

So is this true, or by some SMALL chance something is wrong? The threads are good on both ends so that's not it, it's gotta be different sizes, someone tell me so!