DC10 FLC WERE CLRED FOR A VISUAL APCH TO RWY 28L AT SFO AND INSTRUCTED TO FOLLOW A B737 INBOUND TO RWY 28R. BECAUSE OF THE SPD DIFFERENCE BTWN THE 2 ACFT; THE DC10 WAS UNABLE TO STAY BEHIND THE B737. THE TWR INSTRUCTED THE B737 TO GAR.

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APCHING SAN FRANCISCO INTL FROM WOODSIDE VOR AFTER A 4 1/2 HR FLT FROM MAUI; WERE GIVEN TFC TO FOLLOW FOR VISUAL RWY 28L. WE TOLD APCH WE HAD AN ACFT IN OUR 10:30 O'CLOCK POS; BUT WE DID NOT KNOW TYPE. HE THEN CLRED US FOR RWY 28L VISUAL TO FOLLOW ACFT. AS WE INTERCEPTED FINAL APCH 10 NM OUT WE SAW AN ACR Y B737; INTERCEPTING FROM THE NE FOR RWY 28R. APCH SAID TO SLOW TO APCH SPD (153 KTS) AND FOLLOW THE B737 ON R SIDE. AT THIS TIME WE WERE FASTER AND ALMOST EVEN. THE B737 WAS MUCH TOO SLOW FOR US TO REMAIN A VISUAL AND WE TOLD TWR. TWR ASKED ACR Y TO INCREASE SPD AND ACR Y AGREED. AT THIS POINT WE HAD OVERTAKEN THE B737 AT OUR 3 O'CLOCK POS. WE TOLD TWR THERE WAS NO POSSIBILITY OF US SLOWING. THE ACR Y B737 WAS NOW IN OUR 4 O'CLOCK POS. WE NEVER DID LOSE VISUAL; BUT HAD OVERTAKEN THE B737. AT APPROX 500 FT TWR HAD THE ACR Y TFC ON RWY 28R GAR. I FEEL APCH/TWR SHOULD HAVE BEEN PREPARED FOR THE LARGE SPD DIFFERENCE BTWN OUR ACFT AND PLANNED ACCORDINGLY. WE DO NOT RECALL BEING TOLD CLRED FOR THE RWY 28R VISUAL AND TO FALL IN BEHIND RWY 28R TFC. IF WE HAD; WE COULD HAVE SLOWED EARLIER. THERE IS A 20-30 KT DIFFERENCE IN OUR APCH SPDS WHICH PLAYED A LARGE PART IN THIS CONFLICT.