These are misc parts so other than the part#s on them I don’t have much to go with.Depending on what year your saw is, 2009 through 2018 should be a 503 10 24-05, and 1989 =-1991 takes a 503 10 24-03. I am not really familiar with all the Husky models, but I know on some the serial number tag will have the date of manufacture on it. You may have to call a Husky dealer with the serial number to get the correct pulley. It looks like they changed the flywheel height which is why one pulley had the deeper neck on it.
The 501s I have are for the smaller diameter shaft on the early 61s. All of these are 503sThe shortest one should be 5015 204 01,used on earlier with a "thin" starter cover. With the "thick cover ",you need to use the long neck pulley to reach pawls.
I'll check all the covers I have for differences in height. Pt#s on those are the same as well, I believe.The shortest one should be 5015 204 01,used on earlier with a "thin" starter cover. With the "thick cover ",you need to use the long neck pulley to reach pawls.