I replaced a pump on my Troy-bilt model with a briggs motor. I found the OEM pump part number and put it into amazon and found something that said it was compatible. I'd imagine the sellers on Ebay and Amazon are the same people. Get someplace that will honor a return if it is wrong.
My pump did not look exactly the same, and I did have to shim it with a washer under each mounting point (Which was mentioned in some of the Amazon reviews) so I was prepared for it. Otherwise, works as new, satisfied, will probably have to do it again someday!