Not sure if this applies to your engine (could be another engine brand) but I thought I read somewhere that when the end plate is replaced with the speedseal unit they only use 4 of the knurled screws to hold it on instead of the original 6 countersunk head screws because the oring seal is more effective than the original gasket
I could be completely wrong but I thought I would tell you this just incase it applies to your pump
If that is not correct if you look at this chart http://www.abetterwaytogo.com.au/f.ashx/Speedseal-Life-campatibility-chart_2.pdf would the BM4 kit not work (6 bolt for a DV10) as the 4 bolt kit (AM4) is listed as fitting both the DV10 and the DV20 pumps
My motor is a early model Donk it appear you cant fit the speed seal to the pump the diameter of the pump housing is smaller as well so I cant even drill and tap new holes .I source a pump houses in the future to suit