I replaced a manifold last summer on a TO-30, but I do not know the origin of the new manifold, it came with the tractor when I bought it. If I remember correctly I used a thin open end wrench and 3/8 socket set. I had to purchase a small breaker bar for the 3/8 set as the ratchet would not fit the socket in the close quarters. I replaced all the nuts with new ones. It was a little uncomfortable at times but did get it done and it did not leak.