So I’m looking for a bit more info on a age old topic. I’m doing a boat load of stuff to my 99 300fw and I will start a thread as soon as all my parts are collected but the one thing I’ve been struggling with is the rear end mod. I had a 350d rear end lined up but it fell thru. So here are my other questions. I located a barn full of big reds and maybe some other 3 wheelers and quads. I know you can use a big red rear end for the conversion but what I don’t know is …….

– what year’s can I use from a big red or a sx

– are the 250 axles the same diameter or smaller than the 350d axles. Reason being is i want to know which ones are stronger

– I want the rear axles to be as wide or wider than the stock 300 axles. Can I accomplish this with the 250 big red rear end with out wheel spacers?

– what year did they stop welding the swing arm to the rearend? (Similar to question 1)

-is there a downside to using 250 big red rear end opposed to a 250 fourtrax or 350d