Give aggressor a call, they should be able to help you through this and answer any questions of their products.

http://www.aggressorjets.com/contactus.html

Jason its late and I'm tired but something doesnt "click"! Does the Impeller actually say "aggressor" on it ? The "MB" stamping  thing is an early Dominator (Mar Bud industry). Early Doms usually use a Narrow (different wear ring ,spendy) but will ,with a little work fit your Berk  FYI Aggressor letter designations eg "A" "B" etc are about 1 designation off everyone else so a Aggressor A acts similar to a Berk AA etc A picture would help ! Whatever you decide if you if you buy it double check !!! for skirt cracks ! Tom

Jason bring it up on ebay go to the top "copy" (right click)  the link and then paste it here 

Good Job Jason ! Looks like a "bargy" to me ,that impeller was around 500+ and a good shaft of any kind is worth some bank  Tom

... only thing bothers me is all the "discolorations" on the impleller , was it from a "burn job" ??