I have a set of heads that as I understand were from Tom Hutchinson from the early development of the indy motor before the weslake, and sents they didn't use them they made stock, superstock cheater heads for the 1969 season. They are a set of X heads 11-68 date code and were built in 2-69, they have 5/16" hemi style tulip valves, guides are drilled 5/16" not bushed .100" longer 2.02 1.60, BB battleship springs, hemi retainers and locks, hemi style 3/8" push rods,
pedistals milled down and drilled offset for the longer valves, and the T/A rockers shown in the picture. Here is a artical from Motortrend 7-69.