Can someone tell me what belt numbers to use on my 54 inch deck I just mounted under my LX178? Sticker on deck says 54 muncher compatible. S/N sticker calls it a 54C. Deck came with no belts. And the primary belt for my 38 inch deck is a bit too short for this 54. Also a part number for the tensioning spring on the secondary belt would be helpful also as it was/is missing. Guy I got the deck from couldn't remember what model it was on and this is a bit of a one off set up so I need some help from you experts here! Thank you. And yes the deck itself mounted perfectly. Can't wait to use it!