Steve Guider is a good source of information for the Colt and early Case tractors because he is a collector/restorer. However, Steve is NOT a dealer. Brian Hildreth IS a dealer and keeps a large inventory of parts on hand and will mail your order out promptly. As a bona fide Ingersoll dealer, Brian is very knowledgeable about all the tractors bearing the Ingersoll brand and is one of the most helpful individuals I know. A link to Brian's site is posted below.
Case branded garden tractors were made by the J. Case company at Winneconne, Wisconsin until Case SOLD the division to Jack Ingersoll in late 1983 when it was renamed. Currently, Ingersoll is owned by Eastman Industries and is based in Maine.