The Cordel Gambit
1.e4 e5 2.Nf3 Nc6 3.Bb5 Bc5 4.c3 f5

I was under the impression that 5.d4 has been considered all but a refutation of this opening for some time. On my database 5...fxe4 scores a miserable 16%, with 6.Ng5, 6.dxc5, 6.Bxc6 and 6.Nxe5 all scoring 75% or more... the main line seems to be 6.Bxc6 dxc6 7.Nxe5 Bd6 8.Qh5+ g6 9.Qe2! with a very comfortable edge for white. 6.dxc5 exf3 7.Qxf3 Nf6 8.Bg5 O-O 9.Nd2 d5 10.cxd6 Qxd6 11.Qe2 should also give white a nice edge, though 11...Nd5 (which has been played before) is a blunder, and black should prefer 11...h6 12.Bc4+ Kh8 13.Bh4 Bf5 with at least some counterplay.

6.Nxe5 should allow black chances after 6...Nxe5 7.dxe5 (Or 7.Qh5+ Ng6 8.dxc5 Nf6 with good play) c6 8.Be2 d5 9.exd6 Nf6 10.O-O Qxd6, where black's piece play should compensate for the weakness of the e4 pawn. Or 6.Ng5 seems best met by 6...exd4 7.Nxe4 Be7 8.O-O d5 9.Qh5+ Kf8 10.Qf3+! (I think better than 10.Ng5 g6 11.Qf3+ Nf6 12.Re1 Kg7 13.Bxc6 bxc6 14.cxd4 Rf8! with counterplay) Nf6 11.Nxf6 Bxf6 12.Bxc6 bxc6 13.cxd4 which should grant white a pull.

All in all, if you're looking for an ...f5 pawn push against the Lopez, I think either the Schliemann proper (3...f5) or deferred Schliemann (3...a6 4.Ba4 f5) are better tries for black.

Regards, 
Craig