I recommd novarossi front beraring #17011 , it is the best bearing on the market , I don't think anybody will argue that ;0

As far as the p5 bearing , they do not last very long , right around 3 gallons is about right , replace with 17011 front bearing and you will be a happy camper!!

I have seen the best results as far as low friction from bearings with one shield on the front and exposed balls in the rear . Leaving both shields on will seal the engine up fairly well , it will create a good bit of drag and the bearings grease will dry out fairly quick