on the D6 9U known THE HOOD, i ordered a cheap pulley for driving the alt. it is a 5" with 1/2 bore that i drilled out to 5/8 so the key way was the right size. but i went with the cheap spoked style instead of the solid aluminum one. so after year the spokes all cracked out. today i ordered a solid one to replace this one. should have spent the money right the first time, LOL
(note the alt is mounted this high because i use the same belt as on my td-6 and td-9s)