TBI 7.4 v belt converting to a Johnson/Jabsco crank pump

Hi guys, I had plans this year to swap out the very restricted access mercruiser sea water pump to a crank mounted pump. I bought the Fb-6 Johnson pump or whatever, but I failed to realize that my crank pulley does not have the ever important locating dowels. I know if I just willy nilly it, the sucker will wobble and take out something very expensive. I currently have the 3-groove aluminum crank and 3-groove steel water pump pulley. I looked into a 2 groove steel crank pulley with the dowels, but with the replacement of the old pump I give up groove #2, but I still need to use groove #1 and #3 in their respective positions, as I can't shim or recess the power steering or alternator. All the Mercs I've seen converted with v belts don't have a power steering pump, so am I screwed or is there a doweled pulley for me out there?

Do you mean you will have play in the bolt holes? I installed a similiar unit with the same problem. I used slightly longer bolts but machined up some inserts for the holes to match the OD of the bolts to the ID of the pully flange holes. Mounted and works just fine

Yes that's exactly what I mean, the holes are way bigger than the bolts so I can shift the pump off of centre probably a quarter to half an inch any direction. I do like your idea of making up collars to take up the slack. Is your set-up using the aluminum pulley? Iam asking because there is also ribs on the outer face of the pulley that prevents the two faces sitting flat against each other. A little grinding on the pump flange would probably fix that though. Thanks again, I think I may copy your idea.

I bought steel unthreaded spacers from McMaster Carr. Can't remember the size. worked perfectly.

As a side note check all your hose clamps and hoses carefully. These pumps put out way more volume and therefore the pressure is substantially higher