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victor asta,
First of all, you didn't specify the dealer's action on soft 17 (S17 or H17: I assumed H17 below). Also, when you say "after 80 cards", I assume you meant 80 cards dealt (so a penetration of 80/204 = 39.2%), rather than 80 cards cut off.
To answer your question, we need to know your EV and Standard Deviation (SD), which depend on your strategy and your bet schedule.
For example, if you're simply flat-betting $20 per round and using HiLo for the index plays, then your EV would be about -0.516% (or -$0.1033/rd) and your SD would be about 1.1375 units/round (or $22.75/rd). On the other hand, if you're using HiLo and spreading $5 to $140 ($5 at 0 & below, $40 at +1, $100 at +2, and $140 at +3 & up), then your EV would be +0.680% (or +$0.1355/rd) and your SD would be 8.928 units/rd (or $44.64/rd). In either case, your average bet would be $20 (actually $19.94 in the latter case), but your distribution of results would be quite different.
Your chances of going -$9,513 or worse in 17,500 rounds ($350K/$20/rd) in the flat-betting case are 0.52% (very small, but still only -2.56 SD's), while in the spreading case are 2.21%: small, but only -2.01 SD's and so still not incredible.
Hope this helps!
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