In rereading the post I realzed you were specifically asking about the .46. As you probably know the .46 has been out of production for quite a while. Parts seem scarce by looking through the website listings. The .46 was enlarged to .53 in the eighties and bumped up proportionally in power. The engine then was increased in power by 15% in the late nineties. So the .46 weighs as much as the .53 but is down on power by close to 30%. I love my .53s.
Isn't it amazing how they keep finding more power out of old designs. I wish they still produced their .80 and did the same with it.