66' 273 heads question

It's slightly different around the water port area...where the side gaskets meet the end gaskets (sponges?) I've used RTV and made them work but if you're not carefull, they'll leak.....sometimes water into the lifter cavity which can be a real mess. I think Felpro still makes them but I haven't bought the early set in years so am not positive. I used to have an NOS Mopar set around here somewhere.... if I find it, I'll post a photo of the difference.
Thanks, Mark