Will a 500 head fit on the 425 engine ?

 

Yes,the Magnum 425,Sportsman 500, Magnum 500,Scrambler 500 has the same part number on the head (3085527) plus all use the same cam and intake/exhaust valves until the 2001 Sportsman 500 (2000 model for the Scrambler 500). Only difference on the 2001 Sportsman 500/2000 Scrambler 500 is the HO cam and larger intake manifold for the bst40 carb and that can even be used on the 425 if you wanted to.I'd at least get one with the later model HO cam or just get the head and get a replacement cam on ebay.