Both dowels need to just be on one side, you don’t want them across and in both heads. It’s that way for thermal expansion of the engine. Being on just one side gets the job done, it aligns the blower parallel to the block. You need longer ones when putting the spacers in, 24 mm long if memory serves me correctly. Hopefully they come out easy for you, I’ve yet to have one do such, their a bitch to get out.