I'm not sure what snowthrower I have.It doesn't have any #'s on it or a a tag and can say from using it at the end of last year that it definetly doesn't throw snow like has been desrcibed on here by some of you .I also know that in th early 90's MTD went a 6" pto drive.I'm also looking at putting a 54" deck off of a newer cub that also uses the 6" pto drive and a different style mule drive.Before I use the snowblower this year I am going to tear it down as it seemed noisey to me(I did grease it before I used it or even got it going)I do need to get the extension brackets for it but rebelted it to use it last year.Now I've read on some of the older post that the 450 and 451 used different pulleys/gear ratio's.I can say that the guy I bought this off of must of had alot of spare pieces and made this outta alot of them.Because I had to fix alot of stuff on this thing.How do I know what blower I have and what the story of the 6" pto drive for M18...........Thank You............Jim