Quote from zraythis answer won't address your question, but I feel compelled to mention that a child young enough to need a special seat probably shouldn't be a passenger in any vintage car unless there is no other safer (modern) transportation available. I know infants and toddlers rode in vintage iron "back in the day", but that doesn't mean we shouldn't take advantage of the engineering progress of the last 40 years and thereby keep our kids a bit safer. Just my .02 cents...
Z. Ray
My friend wants to take his family on the club cruises with him as they joined the club as a family. Just because he has a child shouldn't mean he can't take his wife and child with him any more. It's not like this is a daily driver. I would want to share my passion with my family as well.
See your .02 cents and raise you another .02 cents.
RP