This might be the wrong place to ask, but this is a autox rules question. I have a question about the update/backdate rule for sn95 mustangs. I have been asking around and searching online for weeks, but can't find a answer. My question is, can you use GT40x aluminum heads on 95 cobra? I have read everywhere that you can use the gt40x heads on a 351 cobra r spec motor, because the gt40 iron heads and gt40y heads are out of production years ago. I tried calling the local ford dealership for answers. I asked the man on tje phone about my gt40 iron heads and of course he told me they stop production on the heads. I asked him about a replacement head for the cobra irons. The man suggested the frpp gt40x heads. I asked the man if the part number for the gt40 iron was the gt40x. He told me no. So I asked again what cylinder head is the replacement head for the 95 cobra if the irons ar e no longer in production. The man replied back, gt40x. Now im confused.