user8185: [fen "r1bqk1nr/pp2bppp/2npp3/8/2B1P3/2N1BN2/PP3PPP/R2Q1RK1 b kq - 3 8"]

What could be the best possible response to 8. Be3 for black? Would it be pushing the e pawn by a square, or developing the knight to f6?
What are the best possibilities in this continuation?

user13055: I wouldn't go for 8...e5 in this position. When black plays e5 in Scheveningen/Najdorf and even in Smith-Morra gambit, it is usually connected with a win of tempo (attacking the knight on d4) or black is forced to do so because white is threatening e5. This simply isn't the case in the position above, as 9. e5 won't do much harm.
Finally, the 8...e5 move can cause you a lot of trouble because of the weak d5 square and the a2-g8 diagonal. Therefore, I would suggest you leaving e5 for future.

8...Nf6 is a much more logical developing move and I would play it. Not surprisingly, it stands as the move #1 in my database with a great statistic (72.1% for black). For example:
[fen "r1bqk1nr/pp2bppp/2npp3/8/2B1P3/2N1BN2/PP3PPP/R2Q1RK1 b kq - 3 8"]

8...Nf6 9.Qe2 O-O 10.Rfd1 {and only then (when white threatens e5) play 10...e5 yourself} 10...e5 

Another try for black is 8...a6 (covering the b5 square), but I think there will be enough time for that after finishing the development (if needed at all).

EDIT: As @Evargalo noted in the comments, in the 8...Nf6 line I gave above, you can also try 9...Ng4 with the idea of blocking the e5 break by putting a knight on e5:
[fen "r1bqk2r/pp2bppp/2nppn2/8/2B1P3/2N1BN2/PP2QPPP/R4RK1 b kq - 4 9"]

9...Ng4 10.Bf4 Nge5

The key idea of the manoeuvre is that black doesn't mind doubled pawns on the e-file, because he is pawn up and thanks to those pawns he can control the central squares d4 and d5.
Other possibilities shown by @Evargalo are to deviate from standard set-ups in Smith-Morra gambit by playing 10...Qa5 or 10...Bd7, I guess they are at least as good as 10...e5 so thanks to Evargalo for pointing them out.

8185: <pre><code>[fen "r1bqk1nr/pp2bppp/2npp3/8/2B1P3/2N1BN2/PP3PPP/R2Q1RK1 b kq - 3 8"]
</code></pre>

<p>What could be the best possible response to 8. Be3 for black? Would it be pushing the e pawn by a square, or developing the knight to f6?</p>

<p>What are the best possibilities in this continuation?</p>
 13055: <p>I wouldn't go for <code>8...e5</code> in this position. When black plays <code>e5</code> in Scheveningen/Najdorf and even in Smith-Morra gambit, it is usually connected with a win of tempo (attacking the knight on d4) or black is forced to do so because white is threatening <code>e5</code>. This simply isn't the case in the position above, as <code>9. e5</code> won't do much harm.</p>

<p>Finally, the <code>8...e5</code> move can cause you a lot of trouble because of the weak d5 square and the <code>a2-g8</code> diagonal. Therefore, I would suggest you leaving <code>e5</code> for future.</p>

<hr>

<p><code>8...Nf6</code> is a much more logical developing move and I would play it. Not surprisingly, it stands as the move #1 in my database with a great statistic (72.1% for black). For example:</p>

<pre><code>[fen "r1bqk1nr/pp2bppp/2npp3/8/2B1P3/2N1BN2/PP3PPP/R2Q1RK1 b kq - 3 8"]

8...Nf6 9.Qe2 O-O 10.Rfd1 {and only then (when white threatens e5) play 10...e5 yourself} 10...e5 
</code></pre>

<p>Another try for black is <code>8...a6</code> (covering the b5 square), but I think there will be enough time for that after finishing the development (if needed at all).</p>

<hr>

<p>EDIT: As @Evargalo noted in the comments, in the <code>8...Nf6</code> line I gave above, you can also try <code>9...Ng4</code> with the idea of blocking the e5 break by putting a knight on e5:</p>

<pre><code>[fen "r1bqk2r/pp2bppp/2nppn2/8/2B1P3/2N1BN2/PP2QPPP/R4RK1 b kq - 4 9"]

9...Ng4 10.Bf4 Nge5
</code></pre>

<p>The key idea of the manoeuvre is that black doesn't mind doubled pawns on the e-file, because he is pawn up and thanks to those pawns he can control the central squares <code>d4</code> and <code>d5</code>.</p>

<p>Other possibilities shown by @Evargalo are to deviate from standard set-ups in Smith-Morra gambit by playing <code>10...Qa5</code> or <code>10...Bd7</code>, I guess they are at least as good as <code>10...e5</code> so thanks to Evargalo for pointing them out.</p>
