AN ACR CREW FLEW THE WRONG SID.

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I CALLED TO RECEIVE MY CLRNC FROM DORVAL GND CTL. A WOMAN WITH A THICK FRENCH ACCENT READ TO ME 'DORVAL 5 DEP SQUAWK XXXX.' WHAT I HEARD AND COULD UNDERSTAND WAS -- 'DORVALL (SOMETHING) DEP SQUAWK XXXX.' I READ BACK 'THAT WAS THE DORVAL DEP; SQUAWK XXXX.' SHE REPLIED 'READBACK CORRECT.' I WENT TO MY COMMERCIAL CHARTS AND FOUND THE FIRST SID FROM BACK TO FRONT (AS ONE WOULD TYPICALLY SEARCH TO FIND A SID) WAS THE DORVAL 6 DEP. RWY 28 WAS THE ACTIVE DEP RWY. THE SID CALLED FOR A R TURN TO 315 DEGS AND MAINTAIN 3000 FT. I THEN WENT ON TO REVIEW THE NOISE ABATEMENT PROCS ON THE NEXT 2 COMMERCIAL PAGES. AFTER TKOF AND WHILE IN THE TURN TO 315 DEGS; DEP CTL TOLD US TO FLY RWY HDG AND CLB TO FL230. I REPLIED BACK 'BACK TO RWY HDG AND FL230.' THE CTLR ASKED IF WE WERE TURNING. AFTER A FEW MOMENTS OF SILENCE THE CTLR POINTED OUT TO US THAT THERE ARE BOTH DORVAL 5 AND DORVAL 6 DEPS. DORVAL 5 IS FOR JETS AND CALLS FOR RWY HDG OFF RWY 28. I AM NOT FAMILIAR WITH ANY OTHER ARPT THAT HAS MULTIPLE SIDS NAMED THE SAME; ONLY A DIFFERENT NUMBER. A DIFFERENT NUMBER DESIGNATES A REVISION IN THE SID. I BELIEVE THIS 'SAME NAME; DIFFERENT NUMBER' SID DIRECTLY LED TO OUR CONFUSION. RENAMING 1 OF THE 2 SIDS (IE; DORVAL 5 AND MONTREAL 1) WOULD KEEP THIS FROM HAPPENING TO SOME OTHER UNSUSPECTING PLTS. ALSO CONTRIBUTING TO THIS WAS THE ACCENT THE CTLR HAD AND MY LACK OF POS IDENT OF THE ASSIGNED SID.