Yeah i am going for toothless on the drum... being a bit of a pain to draw in cad as im not entirely sure what diamater to have that part on the drum.... im guessing ill work out the PCD as if i was using normal pulleys but turn the one on the drum to the PCD of the larger pulley.... if that makes sense.... trying to do it so i dont need a tensioner.

i think drums could do really well in the future if done right- they do in america... only problem is NST and LS4... building something to take the horizontal impacts is a challenge... thats why the front end has a billet of ali either side wraped in hardox, and all the chassis will be 20mm alumec 89... beefy