I realize the autocross pan is configured differently than a stock pan and the sump is much larger. It also has the corners cut at an angle to allow for movement of the steering linkage, but because of its size, requires everything to be assembled with more precision on location for it to all work well together. With a 50 year old car, this may mean shifting some things around, possibly even cutting and correcting things at the far end of tolerance that has been there since it was built.

Does the center link drag across the sump constantly or it it only hitting as the steering reaches full lock and it it only in one direction or both? Is it just the center link or is the idler or pitman also hitting the corner notch? Again this could mean your mounts allow the engine to sit too far to one side or the other if it is only one corner or one part that hits. Although, it could also be your overall engine location is too far back in the chassis. If it moves forward so the front of the pan is closer to the K frame, that may create the space necessary on the steering linkage side. to move without contact.

If this is the case, then the loosening of mounts and brackets, including the transmission, would be necessary and then the whole thing would need to be pulled forward. Washers or shims between the engine block mounting ears and the mounting bracket may produce enough space to eliminate the contact.

This is a case where the longer quick ratio arms would prevent pan interference with the steering by moving all the linkage rearwards, but if you have confirmed they won't work with your headers, this may not be an option. Since it all together, have you physically confirmed you do not have the space for the longer arms?